Would you expect a normal behaviour from a physically abused kid? Probably not. :/

Based on the little info we have: Tickling and thread is quite normal. Listening behind your door I'd expect from a younger brother, not older. Menstrual cycle preoccupation seems weird. That's really general though- even tickling could be "done wrong" and abusive if the other person felt overpowered...
I wonder though, why ask? Do you need to feel validated in feeling threaten by his behaviour? As I've pointed out already we really can't tell the severity of his actions, only you can