I wouldn't say not wanting to read the scripture or going to church meant going astray.
That's like saying, I don't eat pizza everyday doesn't make me hater of pizza.
I don't read the scriptures everyday, because I believe it is God's will that he stopped me.
Every time it happens, I gain new insight as to what I read previously.
I admit that I don't read the scriptures everyday or go to church often.
But deep down I keep Jesus's in my heart and my mind.
Not only that, I follow Jesus's example rejecting all temptations, fasting, helping, etc.
It is better to DO the part than BE a part.
Start by asking him why he is angry and vulgar which is the root of the problem.
Be around him and show him YOUR example and don't bombard him or question his faith.
Pray that he will return and slowly open his heart up.
God Bless