Boyfriend went off on me and his family

Earlier this month my boyfriend went out for drinks with friends and walked all the way back home because his friends left without him. Be doesn't remember walking back home and the first following day the police showed up to his house for a welfare check some strangers tried to help him because he was bleeding and in only his underwear but he was out of it and kept walking so they called the police. He has no memory of this and the cop told him he could have. Sak test (SA test) but he declined. I thought that wasn't a great idea. He just said he didn't want to know. His mom also said he should but he still declined. He did agree to get an STD test but was negative for everything.

He went off on us because we had dinner with his family yesterday and he was quiet so his mom kept asking was he upset and he kept saying no. I asked was he sure and he yelled that now he's upset. He upset because we are all treating him like a broken child for no reason when for all he knows he got too drunk and just took off all his clothes then he said "Or maybe I cheated and am a horrible person. I don't fucking no." Which was very bizarre to say but I didn't take it seriously because he was clearly losing it. He said he wasn't upset and we all have made him upset and he doesn't know what happened and doesn't want to know and to stop treating him like we know. Then he started crying and having a panic attack. His mom tried to comfort him and he yelled at her to stop and left. He hasn't messaged any of us since yesterday. His mom is going to give it another day before calling for a missing person. I'm not sure what I'm supposed to do while he's gone. I'm worried