Try not to critisize Mr Ammie too much ya'll. I know the behavior might bring back some flashbacks, specially for you guys, but remember she loves the lug and he is only human. Maybe his dad was like that, maybe he was having a bad day, maybe he was constipated, maybe he regrets not concentrating as much on his own talent, whatever..
less critisism, more advice

obviously she should talk to him, and he should probably talk to his son...help her figure out what to say and how to handle the situation as a parent.
I think you should talk to the husband, urge him to talk with his son apologize for yelling at him, assure his son that he loves him and is proud of his effort. Tell him that he seems to be good at football, and if he concentrated a little more on what's going on he might be the star player, team captain ect.
I think sports teaches you how to work with others, how to be supportive in a team and instills a sense of commitment, belonging and accomplishment that is very important to self esteem. Concentrating on the event is part of playing the sport, you can't just show up you have to pay attention.