Background
I have a friend whom I have been very close with for a long time. A few years ago, when we were in high school, he came out to me and told me that he did not want to tell his parents, as they are very homophobic and would hurt him or kick him out of the house. Obviously I promised not to tell his parents or anyone else, and we continued our friendship as normal.
Currently we are both in college. He went out-of-state to get away from his family and live freely, i.e. not have to worry about hiding his orientation. He came back this summer to visit me and his other friends.
The problem
He has been wanting to come over constantly, basically every day, to get away from his family. He does not want to spend time with them - they have said hurtful things to him in the past and made fun of the way he dresses and acts, and he has implied that he has struggled with self-harm because of the way they treat him. Because of all this I was obviously okay at first with him coming over more often than usual, and it was totally fine for a while. He would come over two or three times a week and we would just hang out and spend time together. No problems at all.
However, I am an introvert and I now have a full-time job, and he now wants to spend almost all of my available time together, starting the minute I get home from work. He wants to know when I get home and then immediately comes over then, and stays almost until I go to bed. He also wants to hang out on the weekends. When I say I have other plans or just want a day to myself, he makes me feel bad about it and reminds me of his home situation, and says that none of his other friends are responding.
It has gotten to the point where constantly being around him, talking to him and supporting him is draining me emotionally. When we are hanging out he constantly complains about his family and does not really ask me about my problems (and I have problems of my own). It doesn't feel like a mutual friendship anymore and I'm getting tired of it. I feel like his therapist and his getting-away-from-family hideout, not his friend.
Question
How can I tell him that enough is enough and ask for a break? Obviously I don't want to make his family situation worse or drive him to self-harm, but I cannot take this anymore. I'm exhausted and it's starting to affect my relationships with other people. Does anyone have any advice to deal with this situation as delicately as possible? I really don't want to lose the friendship, I just want him to let me have some time to myself when I need it and not make me feel bad about it.