I think you are so compassionate and a good daughter.
It really sucks when siblings and/or their spouses are not supportive during family crisis.
They are not considering your mom in a sense, what I mean they know the fish give her some joy in life, and here he and/or his spouse aren't even considerate in this. Grrrr!
I go and take care of my mom's cat, mom's dementia has caused her to neglect scooping the litter and grooming the cat, poor thing is almost ferral by now (sarcasm) but in my heart I could never get rid of something that gives her some joy in her joyless world.
When my brother makes remarks, "if you are burdened helping with the cat and mom is too lazy with it, get rid of it!"
Jan, I do not think sons understand the way us daughters do.
I'm not throwing coals on a fire, but they really are a joke sometimes, they see the caregiver can use some care/help to be the caregiver for their parent(s) and they can't even offer that, grrrrrrrr!! I really feel family members can be so selfish when it comes to caring for someone. Your mom is lucky and blessed to have you, always remember you've done and/or do your best, and that is the best you can do. Your health and needs are just as important.
Take good care,
DE

((((((((((( January ))))))))))))