Problems in 22 year marriage.

Aoa. Question on someone’s behalf. Couple has been married for 22 years with 2 kids. First few years were fine but then problem started to arise.there was a big difference in family background.wife was abusive and fought over small matters and rude to in-laws as well. With time husband started to become rude and abusive as well. Now it has come to the point where they fight every day and to make it worse couple of years ago husband married again. It made matters even worse . Wife is always badmouthing husband picking fight all the time and husband is getting abusive as well fighting back. It’s like they are on revenge spree and want to hurt each other as much as possible. Not thinking about kids at all what are they going through. Abusive and very toxic household.unable to divorce the wife as there is no family support for kids. All family members abroad . What should be done in this case? Thanks you