I'm going to tell my mom to stop bringing her friend over to have sex with him at night and have sex with him again in the morning
Is it because you're feeling jealous?
Yes, I wished she loves me the same way she loves her friend.
You definitely should tell that to your mom. She's supposed to put you before her sex partner. She should respect your views on her relationships.
She would get mad at me if I told her.
That may be, but you need to assert yourself and establishment your rights.  If she respects you, it will strengthen the relationship.