Maybe he has calmed down some. Crying twice in a week over his verbal abuse sounds like a lot less than what you endured.
If anything I think it may open your kids eyes more to how he really is. Adults thoughts and the way they see things are different than when you are a kid.
I am sorry the GF is dealing with it, but I am not surprised - are you?
Yes flush the percocet if you can control with something else. Having seen what my husband went through to get off his 10 year prescription pain management opioid dependency - you don't want to go there. From his mouth, watching what it entailed, and from the opinions of his dr. alcohol was (from a physical addiction standpoint) a walk in the park.