I'd rather my step-dad get 2-5 years of prison time rather than 3-6 months.
Why do you want the punishment to be harsher than the original charge?
To teach him a lesson.
It can be somewhat normal for people to not get along with step parents, but it's wrong to wish unnecessary punishments on people. Jail time will not teach your stepdad any more responsibility by locked up longer than what his sentence called for.
He should for what he did to my mom.
Not everyone will agree on the way their house should be run but you need to respect him. Would it be fair to your mom if he were locked up for such a long time she might lose her home. And you both will be homeless.