Many people who suffer from anxiety need assistance to recover. Intervention addresses the individual's condition. Support and necessary treatments allow many individuals to live full and productive lives. this is where you may have to be very strong but doing nothing will not help your Mother. So kudos to you and I will be praying for you.
You are on the right track, talk to Mom. The objectives of an intervention are to provide a plan for the safety and welfare of your Mother while including her in the plan.
An intervention involves three components: 1) the perception of an unmanageable situation; 2) the individual in crisis; and 3) the helper, or family member in your case, who provides aid. Intervention requires that the person experiencing crisis receive timely and skillful support to help cope with her situation before future physical or emotional deterioration occurs.
I am here for you so please know I care and you are doing the right thing by helpingyour Mother. Just remember to take care of you first. You are a good daughter. :)
Now there is a word I know well, overwhelmed. You have our support so keep on talking to us and know that there is always a light at the end of the dark tunnel.
Remember too that you must put your own health first as you will not be able to help your Mother if your not well.
You posted "But it just seems like there's not much I can do." You are right, sad to say, sometimes there is not much we can do. Your Mom seems to be on a path to self destruction and until she accepts that she has problems you can only talk with her, you cannot force her into anything.
She appears to be in denial re her medical issues and is refusing to be compliant with her physician's orders.
I know for you it is sad and very difficult to watch her behave in this manner so do try to remember you are doing the best you can and hope that she will turn around and accept responsibility for her health needs.
You have my support.