How do we do the right thing by his mother without sacrificing our own health, sanity, and well being?

About a year and a half ago, my mother passed away. She suffered from multiple serious illnesses and conditions, and the last several years of her life were difficult and horrible for my family. For her, it was terrible because of her suffering and diminished quality of life, and for me and my brother, because of the demands of care giving and the frustration of being powerless to help her. I talked to or visited my mother every day, sometimes twice a day, for over thirty years. I miss her, and it's been hard to heal and put my life back together. It is just now starting to get better. My husband, through all of this, has been supportive and patient.

Nine months after my mother died, my mother-in-law's husband passed away. Although 90 years old at the time of his death, he was the primary caregiver for my 87 yr old mother-in-law. My mother in law is legally blind due to macular degeneration, suffers from extreme pain due to neuropathy, and the beginning stages of dementia. She can no longer drive and is unable to live on her own; consequently, we have helped her move to a care community where she can get more hands-on assistance. Even so, we are again in a position of caregiving. My husband has two brothers; one lives 12 hours away and the other one hour. Neither seem inclined to take a very active role. We almost never hear from the one who lives twelve hours away. The brother who is closer has visited twice since December.

I am really struggling with this situation. For one thing, the memory of my own mother and our long ordeal is very strong, and I feel something close to trauma at the thought of doing it again. For another thing, although my mother in law is kind to me now, there were lot of years when she was indifferent, thoughtless, or, sometimes, downright unkind to me and/or my children. There's a part of me that feels she values me now because she witnessed the care I gave my mother, and would like the same relationship. In fact, when her husband died a few months ago, there seemed to be almost a general family expectation that I would step in to play the primary role. Not only are my husband and I geographically closest, but I work at home and have the greatest degree of flexibility with my time. I'm not willing to be the primary person, and I have communicated this to my husband. I am willing to help when I feel able, and have also taken on the task of managing her financial affairs. But on a daily or otherwise regular basis - no.

This places the greatest burden on my husband, and I can see the stress that it is placing on him, and by extension, on me, our marriage, and our lifestyle. I feel guilty and helpless. I don't know what to do to help, or what other role I should be playing, if any. I'm very cognizant of how hard it is to try to hold down a job, yet always be one phone call away from daily disruption or the semi-urgent medical issue of the day. Weekends are spent trying to deal with medications, running errands or otherwise managing her affairs, or just trying to keep her company. She doesn't recognize the efforts made on her behalf and complains constantly about the ones she does. My husband is resentful and feels trapped. He loves his mother, but has always seen that she's self-centered and spoiled. She was always a social person, but she is not adapting well to this community, which is one of the most luxurious with the best activities program in the city. She refuses to make friends, take her meals in the dining room, or participate in activities. Knowing how isolated she is makes my husband feel even more responsible. My husband is ten years older than I am. I am worried about what this is doing to him. I'm worried about the long term effects of this situation. And I'm worried about our life. We had hoped to to retire in a couple of years and enjoy our time together after decades spent working.

What should I do? Can I do more? Is there some way to deal with all the complications of this situation that I'm not seeing? How do we do the right thing by his mother without sacrificing our own health, sanity, and well being?