Dave this is assuming she did find her husband physically attractive once upon a time. If she married him for his money or his mind that's another thing altogether. Our family's older ladies say their spouses are much hotter today than they were in their 20's or 30's.
So yes I meant to say that is true if her spouse is still attractive to her because he makes the effort to be attractive to her (and of course it goes both ways - those pink curlers are not a turnon).
If she has serious illness of course she needs to get well first but it's not a given that older women aren't interested in sex. They may not be interested in sex with their husbands who lack good grooming and have forgotten the little things that keep a marriage interesting.
A talk show host was discussing a recipe for "better than sex" cake - I think I mentioned this before - and he said "People if you think cake is better than sex, you are with the WRONG PERSON." AMEN Brother!