I'm scared my boyfriend may go into a depression if I leave him
What makes you think he will go to depression?
He couldn't handle his father leaving him, he cried for a long time and I had to take care of him
Have you encouraged him to reach out to professionals about his depression?
I'm good at dealing with other people's depression and sadness. I can help him.
Taking all of the responsibility on your shoulders isn't going to fix your boyfriends issues. You need to encourage him to seek professional help.