If he catches up with the imam when he is prostrating or sitting

No File Exists
Check below answers in case you are looking for other related questions:
Joining the imam in any position
Is it permissible to pray in a room where there is a television that is on?

No File Exists
Related Answers:
Imaam waiting for members of the congregation during rukoo’
Passing in front of someone who is praying
They prayed behind someone who did not say the takbeer and tasleem out loud; what is the ruling on their prayer?
Joining the imam in any position
Is it permissible to pray in a room where there is a television that is on?

Recommended answers for you:
He has a number of questions about zakat al-fitr
Is it sunnah to shave the hair of a newborn girl?
His wife is not very interested in intercourse so he resorts to masturbation
Differences in Prayer for Men and Women
Husband and wife taking a bath together and looking at one another’s private parts