I have been with my husband just over 17 years ... His aunt May practically raised him ( so to speak ..weekends, holidays )... He was 100 % loyal to her and trusted in her... I too trusted this woman and a few of his family members...In saying that there was something about her I didn't like.. she was moody at times and I couldn't quite put my finger on it.. but the woman loves to dominate and boss you around...My husband wore rose tinted glasses ..
You need to pay a visit to the Police station BM.
You also need to take the kid to the GP for a couple of councilling sessions. The kid may or may not need them but its best to play safe in these situations.