How to help a family member in need

Hi everybody I have been dealing with anxiety and depression for many years.I am now 46 and want to make changes in my life.My sister is having serious issues now.She has been depressed for a long time but never went for help.She lives with my mother and father with her two kids ages 13and15.She married a verbally abusive alcoholic 15 years ago.They are still married he lives with his father and provides no support for the kids.He takes the kids on weekends and says nasty things about my parents who are supporting the kids.I think this is terrible.Asfar as I know he does not drink around the children.He takes them out spends his fathers money on them fun stuff like the movies,tennis,dining out etc.He makes my sister out as the bad parent.Because she insists on them doing there homework before playing and sets limits on how late they can stay out.My sister only works one day a week.Her car broke down at his house and he said he would fix it.That was over 2 weeks ago.So my sister has no car,she is almost broke,my parents support everybody.They are getting stressed.To sum it up my sister is miserable,depressed,and sleeps alot.I have advised her to see a therapist,a lawyer,the dept of child support but she has done nothing.I have had long talks supporting her.I do not know what else I can do.I am trying to recover from depression also but to see my sister like this really upsets me.Is there anything else I can do? Any suggestions I can not spend to much time at that house it really brings me down.But I always go once a week.Any advice would be great.THANKYOU