every situation is different, so i can't tell you when you should and shouldn't.
but i will tell you from my personal experience, i had to deal with my mom who in her later years was more or less bed-ridden and she would call me, make me come and be with her, and just take away otherwise precious time in my life to just be there when i clearly didn't want to, or i had other work i needed to do.
i tried for a long long time to always be there for her, but in time i just grew to resent and hate every moment of it, and i stayed out of the house as much as possible to avoid any contact with her.
Now, looking back, my greatest regret wasn't so much that i didn't spend time with her, but rather i didn't pace myself and set aside time for me to just be me. because i forced myself to be with her all the time, she became somebody i hated, which nobody should have to say about their mom
So what i offer is this. Play it by ear, and judge for yourself
and it is perfectly fine to ignore the call and be yourself and to do things you want to do. Cause i don't want you to hate her in the same way i hated my mom