On today's standards, they definately would not be considered good fathers. Today, fathers are more "hands on", whereas back then in the sixties, fathers were the breadwinners, while the mother tended the house and the children. It wasn't neglect on the fathers part, it was just not his job. When we see Ennis with the two crying babies, he looks awkward, and really does not know what to do, so passes them on to Alma. Thats not to say fathers of that era did not love their children, it was just not their responsibility to do much more than go to work to earn an income to support them.
Once Ennis and Alma divorced, that responsiblity did not change as far as Ennis was concerned. There would rarely have been an occassion back then when the children would have lived with the father and not the mother, because that was the role of parents then. Alma going to work in the store would probably only have come about because of the seasonal work Ennis did, it would have been quite odd in those times for a man to be home looking after the kids while his wife was out working, but as we see, when he did get work, it took precendence over Almas job.
Jack seemed to be a more hands on father than Ennis was. In some ways, Laureen was the stronger and more professionally employed than Jack was. Maybe thats how he was made to feel in the fathers company, and thats the role he took on. But Jack makes it very clear, that he would have walked away from his wife and son in an instant, if Ennis would have gone with him.
It seems that every time Ennis got holidays or a break from his job, he would go away with Jack. It would be unlikely that he ever took Alma and the kids on a holiday, or even just spent the time at home with them. To just up and go away "fishing" was a pretty selfish act, but not that uncommon for fathers of that era. It was mans business, no place for wives and kids anyway if a man wanted to go away with his mates on a fishing trip or something similar.
For the time, Ennis and Jack were probably not much different to most of the other kids fathers, except of course that they were not really going "fishing". What they did, the time they spent with their kids would have been acceptable, and no one would question their qualities of being a good or bad father.
The fact that Ennis did stay in the kids lives after the divorce, was probably the greatest compliment to his fatherly committment. A lot of fathers back then, just went away and started a new life, but Ennis stayed nearby, and it was partly his need to stay near them, that he didn't go off to live in Texas near Jack. He could have, and a lot of men would have, but he didn't. It is irrelevant if he saw them once every two weeks or once every two months, he was still close by and he still had a relationship with them, that definately makes him a good father.