My boyfriend has no where else to go but I still want to kick him out.
What makes you want to do such a thing to him?
He constantly talks about his mom and I'm annoyed and tired of hearing his complaints.
I get annoyed with people too sometimes, so I understand how him constantly talking about his mom could be frustrating. But that's a small thing to be annoyed by, and far less of a reason to kick him out. Perhaps you and your boyfriend can visit his mom and you can figure out what the issues are and see if she needs help with something that you and your boyfriend can assist her with. This might make your boyfriend feel better in regard to his mother.
Fine. I'll try that but he needs to stop telling me about his mother.
I think it's great that you're willing to try to make the situation better as kicking your boyfriend out would be wrong, especially since he would have nowhere else to go. Helping repair his relationship with his mother could be beneficial to all three of you moving forward.