:sl: brother
Sorry for the late reply. You haven't divorced so that is good. Yes agree to the meeting. See what your wife has to say and what your concerns/problems are. Be patient and do dua that ALLAH(SWT) makes it easier for all for you.
You say your not comfortable with her brother being there so tell her to bring her mum and you can also bring your mum. Or you can take your sister and your wife can bring her sister.
You have a young son so work things out InshaALLAH and be there for him.
If you fear a breach between them twain (the man and his wife), appoint (two) arbitrators, one from his family and the other from her's; if they both wish for peace, Allah will cause their reconciliation. Indeed Allah is Ever All-Knower, Well-Acquainted with all things. Surat An-Nisā' (The Women) - (4:35) - سورة النساء
:wa: