Paradise is the abode of honour that Allah, may He be exalted, has prepared for His believing slaves. In it are delight and happiness such as have never entered the mind of man and no one has ever imagined. Whoever enters it will find true, eternal happiness and will have attained a great victory. Allah, may He be glorified and exalted, says (interpretation of the meaning):

“No person knows what is kept hidden for them of joy as a reward for what they used to do”

[as-Sajdah 32:17]. 

Part of the happiness that Allah has guaranteed to His believing slaves is that He will reunite the family, parents and children, after they all enter Paradise by the mercy of Allah and the intercession of Prophet Muhammad (blessings and peace of Allah be upon him). This promise is mentioned in the holy Book of Allah, in the verses that will be recited until the Day of Resurrection, in which Allah, may He be exalted, says (interpretation of the meaning):

“And those who believe and whose offspring follow them in Faith, to them shall We join their offspring, and We shall not decrease the reward of their deeds in anything”

[at-Toor 52:21]. 

Ibn ‘Abbaas said, commenting on this verse: 

Allah will raise the offspring of the believer to the same degree as him, even if they are lower than him in terms of good deeds, so as to bring joy to his heart. Then he recited the words (interpretation of the meaning):

“And those who believe and whose offspring follow them in Faith, to them shall We join their offspring, and We shall not decrease the reward of their deeds in anything”

[at-Toor 52:21]. 

Narrated by Ibn Abi Haatim in at-Tafseer, and by Ibn Abi’d-Dunya in al-‘Iyaal (no. 357), and by others. For more information see: Tafseer Ibn Jareer at-Tabari, 22/467 

This promise is confirmed by what Allah says elsewhere (interpretation of the meaning):

“Adn (Eden) Paradise (everlasting Gardens), which they shall enter and (also) those who acted righteously from among their fathers, and their wives, and their offspring”

[ar-Ra ‘d 13:23]

“Enter Paradise, you and your wives, in happiness”

[az-Zukhruf 43:70]. 

Al-Haafiz Ibn Katheer said in Tasfseer al-Qur’aan al-‘Azeem (4/451): 

The words of Allah, “and (also) those who acted righteously from among their fathers, and their wives, and their offspring” mean: they and their loved ones among their fathers, wives and offspring, of those who were believers and qualified to enter Paradise, will be reunited so as to bring joy to their hearts. And they will be raised from a lower degree to a higher degree without that detracting from the higher degree; rather that is a blessing and favour from Allah, as He says (interpretation of the meaning):

“And those who believe and whose offspring follow them in Faith, to them shall We join their offspring, and We shall not decrease the reward of their deeds in anything. Every person is a pledge for that which he has earned”

[at-Toor 52:21].

End quote. 

It says in Fataawa al-Lajnah ad-Daa’imah (vol. 2, p. 409): 

Question: Will we meet our children in the Hereafter, as all of us are hoping for that? We hope that you will explain this matter for us and tell us of everything that you think is good. May Allah reward you with the best of rewards. 

The response was: 

Allah, may He be glorified and exalted, has told us that by His grace, blessing and kindness He will  make the offspring of the believers join their fathers in the same status, even if they did not reach the same status in good deeds. Allah, may He be glorified and exalted, says (interpretation of the meaning):

“And those who believe and whose offspring follow them in Faith, to them shall We join their offspring, and We shall not decrease the reward of their deeds in anything. Every person is a pledge for that which he has earned”

[at-Toor 52:21]. 

Shaykh Ibn ‘Uthaymeen said in Fataawa Noor ‘ala ad-Darb (Aqeedah (belief)/ Belief in the Last Day): 

When a person enters Paradise, will he recognise his relatives? Yes, he will recognise his relatives and others, which will bring joy to his heart, because Allah, may He be exalted, says:

“(there will be) therein all that the ones inner-selves could desire, all that the eyes could delight in, and you will abide therein forever”

[az-Zukhruf 43:71].

Indeed a person will be gathered with his offspring in one status even if his offspring are of lower status than him, as Allah says (interpretation of the meaning):

“And those who believe and whose offspring follow them in Faith, to them shall We join their offspring, and We shall not decrease the reward of their deeds in anything. Every person is a pledge for that which he has earned”

[at-Toor 52:21].

End quote. 

Secondly: 

We should differentiate between two things here: 

-1-

The people of Paradise will visit one another, recognise one another and meet one another in the Gardens of delights. This is part of the perfect delight of the people of Paradise. There is nothing to prevent someone of a lower status in Paradise from visiting one who is above him, as also happens in this world. 

Allah, may He be exalted, says (interpretation of the meaning):

“Then they will turn to one another, mutually questioning.

A speaker of them will say: ‘Verily, I had a companion (in the world),

Who used to say: ‘Are you among those who believe (in resurrection after death)?

‘(That) when we die and become dust and bones, shall we indeed (be raised up) to receive reward or punishment (according to our deeds)?’

(The man) said: ‘Will you look down?’

So he looked down and saw him in the midst of the Fire.

He said: ‘By Allah! You have nearly ruined me.

‘Had it not been for the Grace of my Lord, I would certainly have been among those brought forth (to Hell).’

(Allah informs about that true believer that he said): ‘Are we then not to die (any more)?

‘Except our first death, and we shall not be punished? (after we have entered Paradise).’

Truly, this is the supreme success!

For the like of this let the workers work”

[as-Saaffaat :50-61]. 

Ibn Katheer (may Allah have mercy on him) said: 

Here, Allah, may He be exalted, tells us about the people of Paradise: they will turn to one another and ask one another about their situation, how they were in the world and what they used to suffer there? This is an example of their meeting and conversing over their drinks, whilst they are sitting on thrones, with servants around them, coming and going with delights such as food, drink, clothing and other things that no eye has seen, no ear has heard, nor has it entered the mind of man.

End quote from Tafseer Ibn Katheer, 7/15. See also Haadi al-Arwaah by Ibn al-Qayyim, 1/259-263 

With regard to fathers and sons, or other family members, being gathered in the same level of Paradise on an eternal basis, what appears to be the case – and Allah knows best – is that this applies only to those who die in childhood and their parents; Allah will bless their parents in Paradise and raise the children to their status, so that they may have the joy of being with their children there. 

Ibn al-Qayyim (may Allah have mercy on him) said, after speaking of the difference of opinion concerning this matter: 

It seems most likely that only those children who died in childhood are singled out in this case. No one of a lower degree could join someone of a higher degree, and the fact that children will join their parents is something natural, because a man usually has his children with him. And Allah knows best.

End quote from Haadi al-Arwaah, 398 

This is also the view favoured by Shaykh al-Islam Ibn Taymiyah (may Allah have mercy on him). See al-Baab al-Maftooh, 4/161 

See also the answer to question no. 5981 and 10144

And Allah knows best.