He lives with his son's family <members>.

[dorajikkot]

Hello,

1. A friend of mine lives with his son's family/his son's family members.

2. He lives in his son's house/in the house of his son.

Please, help me choose the right phrases in the sentences.

Thank you for your help.

 

[grassy]

Hello,

1. A friend of mine lives with his son's family /his son's family members.

2. He lives in his son's house/in the house of his son.

Please, help me choose the right phrases in the sentences.

Thank you for your help.

 

[Myridon]

"His son's family members" would not include his son (but might include himself as he is his son's father).
It would actually a bit simpler to say "A friend of mine lives with his son." We will assume that the son's wife and children also live there.