She lives an extremely dysfunction life. I have noticed a dramatic change in her personality these past 8 months or so. She is severely depressed telling me that she is "at the bottom of the barrel". I have suggested all sorts of potential things to help her. Do I contact her PMD to let her know my concerns? Do I just listen and not offer suggestions? She is drinking which is something new. I am extremely concerned.
Just mulling this over with you ...
There is a common answer we give on this site when someone shows changes in behavior. It's to check her for a UTI (urinary tract infection). This infection is easy to check. The patient doesn't always realize they have it because they don't always have recognizable symptoms but it can cause a person to behave as if they have dementia. An antibiotic is all that's necessary to cure it. Left untreated it can cause severe problems. If she has never had one she might not know to ask for a check and many drs seem to not know to run this simple pee test. She could run by an urgent care for the test or even pick up a kit at the drug store. If the test is positive she could call the dr for an antibiotic.
Medicare will pay for therapy. Encourage your sister to see a therapist to discuss her problems.
Also encourage her to exercise. Ask her to go for walks with you. Of course the drinking to excess will make everything worse. It's wonderful that you want to help your sister. We often advise caretakers to slip notes to their elders doctors giving them a heads up on issues the elder won't discuss on their own. My sister has asked me to leave her drs office before because I was telling too much family info. We laughed about it but I knew she was serious about me butting out. It's a hard call. With the conditions you describe it sounds like she needs to toughen up in order to keep her husband from running her over. Living with that kind of stress will take it's toll. If her dr has changed her meds the alcohol might not be appropriate with some of the new meds. I think I would tell her that I had noticed a change recently and that I was concerned. By her comments she has noticed a change too. If husband has always been a jerk you would think she'd be used to it, so tell her you are concerned it might be something more. My friend and I decided that we would tell the other when we noticed changes that might need to be checked out. Someone to watch each other's back. Perhaps that's something you could consider. It might be awkward to get the conversation started but once you got going it would get easier. Tell her you want her to win, not BIL. You might also talk to her about giving you or one of her kids her POA.
If BIL doesn't have her best interest he shouldn't have the POA. She doesn't have to broadcast it, just get it taken care of.
She's lucky to have you in her life.