He's pressuring your mother to live a life stripped of small joys over pennies. What wonderful thing is he going to use the money for in the future that will make all the daily petty misery he causes worth it? Odds are, nothing.
Madness string 101805
Abused people tend to abuse people. Children that are constantly abused and look to the community around them and see that the community also encourages abuse will more likely think that abuse is okay until something happens that gives them better perspective. The only thing that comes from continuing to berate someone for their past is more negativity and hate. Instead of continuing a cycle that has been alive and thriving since before Rome fell, we should focus on change. Focus on changing ourselves constantly to be better, and focus on celebrating others as they also change themselves for the better. Continuing to drag someone for past actions they already understand were wrong helps no one.