Drug question, possibly coke or meth?

my step dad goes to this bar a lot. the owner is known for doing coke. now my step dad goes there all the time and on weekends he works there. he came home yesterday and started freaking out and calling my mother names that he NEVER does. he then picked up some spaghetti that was in the pot and threw it at her, getting in her face and pushing her. now she just got over throat cancer and she has a traech(sp?) and she is extrremely fragile. now, ive never seen him angry when hes drunk: hes a happy drunk, so i know thats not it. what ive been thinking that he too now is doing some sort of drug. and btw, i have never seen him lay a finger on her before yesterday.. so is this a sign of coming down from a coke high? or what?