I have DS1's friend here (as a favour to his mum, past experience has taught me not to volunteer to offer to have him for tea) and his behaviour is a nightmare. In the past hour he has continually slammed the glass living room door, taunted younger ds2 relentlessly, keeps calling the 9 month old baby ugly, trashed ds1's room and shouted rude words in our street. DS1 is desperately trying to get him to stop bouncing on the sofas and watch a dvd. DS looks really worried 
I keep telling him off and it is literally like I don't exist, he looks straight through me. His lovely mum will undoubtedly ask how he has been. AIBU to say actually his behaviour has left alot to be desired?