Relation between nephew and his aunt.

I have a muslim friend that told me that he likes and he plays with his aunts breasts in front of his family. I was disgusted by this behavior and he told me i am wrong. I want to know if it is moral and corect for a nephew to play with his aunt's breasts? I know that my question might sound stupid but we had a terrible fight because of this subject and i just want to know which one is wrong in this story. Thank you for according me your time.

Dear Brother / Sister,

The primary mahram (a very close relative that a person cannot marry) men for a woman are as follows: Her father, father-in-law, her husband’s son from a previous marriage, her brother, her brother’s or sister’s sons, her paternal and maternal uncle, her foster brother (breastfed from the same woman)…
The evaluation of the faqihs (scholars) about the issue is as follows: The head, hair, neck, breasts, ears, wrists, arms, shins and feet of a woman are her ziynahs. There is no drawback in terms of Islam for a woman to expose them when her mahram men are present. However, it is haram for her to expose her waist, abdomen, back and legs above her kneecaps even to her mahrams. The kneecap is included. (Al Mabsut – Shamsulaimma Sarahsi)
The permission for a man to look at the ziynah parts (mentioned above) of mahram women is valid for her permanent mahrams not for temporary mahrams. Therefore, it is haram for a man to look at the ziynah parts of his wife’s sister; and it is haram for his wife’s sister to expose those parts when he is present. It is because they are mahram temporarily. That is the sahih (sound) opinion. (Fatawayi Qadihan – Al Muhit – Radiyuddin Sarahsi)
A man is allowed to look at the ziynah parts of mahram women if he does not look at them lasciviously. If he feels lust when he looks at them, then it becomes haram for him to look at them. The same decree is valid for touching those places.
It is haram for a man both to look at and to touch the back, waist, abdomen, sides, and legs above the knees including knees of mahram women whether she is her mother, sister or any other close relative except when it is absolutely necessary. (Al Muhit – Radiyuddin Sarahsi – Fatawayi Hindiyya)
The son of a woman is allowed to rub her above-mentioned places over a dress when it is necessary because he is the closest person to his mother.

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