My boyfriend and I live in Mother's home (she no longer Lives there) He is not helping pay bills and I want out of the relationship. We have been living together for three years now. He receives mail at the house. We do not have a lease with my mother

Your mother would have to evict him according to Pennsylvania law.

Pennsylvania Evictions

Agree with Judy. He is a defacto tenant. You have to file against him as though he has a lease. You do NOT have the authority to toss him out and your mom has to initiate this as the property owner.

He is a resident, not necessarily even any type of tenant. He must be evicted by your MOTHER. You have no legal standing to do anything

He will have to be given legal notice and evicted though the courts.

You can of course just yell at him, tell him to get out and see if he leaves.