it must be difficult for the guy coz he doesn’t know how to handle between his mom and girlfriend even the girl is supportive but they are both in pain maybe the mother too. it’s easy to say but you can’t stop the emotions. The mom must be feeling jealousy as his son was always been with her before and now more often spending time with his girlfriend so she feel lonely. The son is the most suffering and suffocating from all the situations so he decided to let go as you can’t change the fact that it is your one and only mother wether if she done the horrific things or say ridiculous words it still your mom who give birth to you.