How do we make Dad comfortable and safe without setting off Mom?

Dad is in hospice at home, mom is caregiver but their relationship is toxic. My parents have had MANY issues over their 50+ year marriage, my mom has been his caregiver for years, but now that dad is home their toxic relationship is taking it's toll on not only my dad but us kids as well. My mom is controlling beyond belief and creating toxic relationships with all of us as well. We don't want to see my dads last days spent in an angry negative environment. We don't know what to do?