Praise be to Allah

Firstly: 

The maternal aunt has a high status in Islam, which is similar to that of the mother, as Abu Dawood (2278) narrated from ‘Ali (may Allah be pleased with him, from the Messenger of Allah (blessings and peace of Allah be upon him), that he said: “The maternal aunt is of the same status as the mother.” Classed as saheeh by al-Albaani in Saheeh Abi Dawood. 

And it was said that what is meant is that she is of the same status as the mother with regard to being entitled to custody, because the hadith was narrated concerning that. 

Fath al-Baari (7 /506) 

And it was said that her status is equivalent to that of the mother with regard to custody and other matters. 

Adh-Dhahabi said in al-Kabaa’ir: That is, with regard to showing kindness, honouring, and upholding ties of kinship with her. 

See also: Sharh Buloogh al-Maraam by Shaykh Ibn ‘Uthaymeen (5/203) 

The second meaning is supported by the report narrated by at-Tirmidhi (1904) from Ibn ‘Umar, according to which a man came to the Prophet (blessings and peace of Allah be upon him) and said: O Messenger of Allah, I have committed a grave sin; can I repent? He said: “Do you have a mother?” He said: No. He said: “Do you have a maternal aunt?” He said: Yes. He said: “Then treat her kindly.” 

Classed as saheeh by al-Albaani in Saheeh at-Targheeb (2504)  

This indicates that honouring one’s maternal aunt and treating her kindly come under the heading of virtuous deeds and acts that expiate sins. 

Abu Dawood (4970) narrated from ‘Aa’ishah (may Allah be pleased with her) that she said: O Messenger of Allah, all my friends have a kunyah. He said: “Call yourself by the name of your son ‘Abdullah” – meaning the son of her sister. Musaddad said: ‘Abdullah ibn al-Zubayr. He said: So she was known by the kunyah of Umm ‘Abdullah. He was ‘Abdullah ibn az-Zubayr, the son of her sister Asma’ (may Allah be pleased with them all). 

This hadith confirms what is mentioned above, that the maternal aunt is of the same status as the mother. 

So the Muslim should treat his maternal aunt in a kind manner, just as he treats his mother. 

See the answer to question no. 148430 

Secondly: 

A person’s maternal aunt – or his paternal aunt – is a maternal aunt to him and to all of his descendants, or a paternal aunt to him and all of his descendants. So your father’s paternal aunt is a paternal aunt to you, and your father’s maternal aunt is a maternal aunt to you; the same applies to your mother’s paternal aunt and maternal aunt. 

See the answer to question no. 34791 

Thirdly: 

A man’s maternal aunt is one of his mahrams, so it is permissible for him to shake hands with her, be alone with her and travel with her, and it is permissible for her to uncover her face in front of him, as a mother does in front of her sons. 

It is permissible for a Muslim woman to uncover in front of her mahrams and women like her that which usually the case with people of religious commitment and good conduct, such as the face, head, neck, forearms and part of the shin. 

It is not permissible for her to wear short or see-through clothes in front of them, or tight clothes that show the shape of the ‘awrah. 

See the answers to questions no. 82994 and 43480 

And Allah knows best.