Is he just lying again, or is he actually telling the truth?

My boyfriend has ADHD. His mother is a alcoholic, and his brother and sister use drugs. I know those are the true strait down facts. But recently he's been leaving early from school. Today I got up the nerve to ask him why he was leaving. He told me his parents were letting him, but I knew he was lying. At first he didn't want to tell me because he didn't think I should know because it could hurt me. I said I was ok with knowing. He finally said he was going to a mental hospital. At first I was like, you lying again. I said that harshly to him. But then he started to get really upset, and said that was the truth and it was the Natchaug Hospital, which I just checked was a real hospital that helped with people who need emotional help. But I'm still worried he could be lying to me. Do you think he is? All the facts are there for what he told me, but I'm just not sure about it.