Helping my boyfriend

Hi. My boyfriend and I recently broke up because i felt disconnected from him and he said he couldn’t do anything about it. I later found out that it is because of him being schizophrenic and him having a rough past. I feel awful and I want to help him because I know he doesn’t have anyone that will. He thinks so negatively about himself and I just want to know what I can do and what I can learn. I want him to be happy. This is killing me. He says it is too late for me to help him but I know that’s not true. I care about him too much to just not do anything.