Is there any evidence in "To Kill a Mockingbird" to suggest Bob Ewell is a bad father?Besides the fact that he shoots year round and his children...

A good place to look for further evidence of Bob's rather infamous career as a father is to take a look at Mayella's testimony to the courts in chapter 18.  In her testimony, she reveals just how hard of a life she has living with her father and all of her siblings.  She says that her father always took the money that they got from the relief check and

"drank it up anyway--sometimes went off in the swamp for days and came home sick."

So, he not only used all of their money for buying booze, but would disappear for days, getting drunk and coming home too sick to care for the kids. So basically, he abandoned small children for days on end.  That alone is enough for child protective services, today, to take his kids away from him.  It is also implied that he beats his kids when he has been drinking.

Also, look at the events that prompted the trial.  We can gather that Bob, upon discovering Mayella putting the moves on Tom, came in in a rage and beat her nearly senseless.  Her wounds were from a fully able, two-armed man; he nearly choked her to death.  So, this is another indication that he is an awful father--he would nearly kill his daughter (the one who took care of all of the kids) simply because she liked a black man.  In reality, she was incredibly lonely and was reaching out.

So, in addition to not forcing his kids to go to school, and being gone a lot, he is a drunk, he abandons his kids, beats them, and nearly murders one of them.  Bob Ewell is not the best example of a good father, to say the least.  I hope that helped; good luck!