There may be a lot more involved than that. It could be a matter of trying to do what's best financially in the long run, for the purposes of getting medical care that he needs. I'm not claiming to know that, just speculating that after being married for that long, it would surprise me to find out that it's a simple cut and dried case of her not caring about him after all that time. Especially at her age.
Similar to what happened with my maternal grandparents.
My grandfather, for the last several years of his life, was in very poor shape, being kept alive only by rather extreme and expensive medical technology. He really didn't want to live that way. My grandmother asked how long they intended to keep him that way, and was told that they intended to do so until the money ran out.
My grandmother divorced my grandfather, so that their assets could be divided. They kept my grandfather alive until his share of the money ran out, and then they pulled the plug, while my grandmother was able to live out the rest of her life on her share of the money that she had thus prevented from being consumed.
I don't recall that, after the divorce, it took very much longer before my grandfather's share ran out, and they finally pulled the plug on him; but my grandmother's share was enough for her to live quite well for another ten years or so until she came to a more natural end. They had once been very wealthy, my grandfather having been a very successful businessman in his younger days.
Had they not divorced, the entire remainder of their fortune would probably have been used up in less than year on my grandfather's ongoing medical costs, at which point they would have pulled the plug, and my grandmother would have been left destitute.
The exact situation that occurred with my grandparents, I do not think would occur today. Laws and policies are different, such that a man in the condition in which my grandfather was would now be allowed to decline the use of such extreme and expensive means to artificially prolong his life.
But I have to wonder if some vaguely similar situation might be involved here. Perhaps there is some situation that is causing an excessive financial drain on their dwindling assets, that can be remedied by legally dissolving the marriage.
