My mum doesnt sleep at home?

l need help on what to do.my mum doesn`t sleep at home.sometimes she goes a whole weekend and puts off her mobil phone.when she comes home,no one dares asks her where she has been because they fear her.she verbally abuses my dad and doesnt make food for him.he is incapable of supporting himself coz he is old and has diabetes.my young brother told me to help them because l am the only one that dares tell mum when she is wrong.l live in another country and so its hard for me to do anything about it.whenever l call mum and tell her to take care of dad and my young brother (17yrs)we end up quarreling and she starts verbally abusing my brother and dad for telling me.the only soulution l would like to try is to employ a house help who will be taking care of domestic work and especially making food for dad.that also might not work as my mum can chase her away.my dad has houses that he rents out and since he has a memory loss,my mum is the one that collects rent,meaning she is the one to buy the neccessary things at home including food.we have always had problems with mum when growing up,she was drinking and l cant remember her spending a weekend at home unless she was sick.l am 30 yrs old now and l am really angry at my mum for treating my father like crap.please any suggestions on what l can do to help?