Seeing we may not have the nuances of your situation and we are not priests nor spiritual counselors, it would not be prudent to even take a guess at an answer. Your question falls outside the scope of our mission: to clarify and correct misperceptions about the Catholic faith.
I will say the only power the devil ever has over anyone, is the power we allow him to sway over our lives. Your husband should be able to fill you in on the great benefits of the sacramental life of the Catholic Church.
Lutherans, (except maybe for the Scandinavian Lutherans), don't believe in Apostolic Succession. therefore some of the sacraments they administer are not valid. Valid sacraments they do have would include Baptism, if the correct Trinitarian form is used.
The sacraments of the Catholic Church allow us to partake in divine nature and make us spiritually strong so we can ward off the demonic in our lives.
The word sacrament comes from a word meaning "to swear an oath". For each of the seven sacraments, God is swearing to do his part, but expecting us also to do our part.
The only recommendation I have is for you to ask your husband to get some pastoral guidance from either the pastor or a priest at his local parish.
At a certain age, people like your mother's husband can only change with the help of our prayers, and even then, they have to be open to the grace they receive from our prayers.
This is one of the good, [and bad] sides, of people's free will. They have to choose to change, even if it includes letting go of sub conscience grudges in their life.
If someone doesn't wish to change their bad behavior, they will be accountable for it at their particular judgment, their one on one, with Jesus.
I hope this helps,