My 94 year old mother who lives in a nursing home has a terrible time with constipation. Any suggestions?

Miralax or citrucel; if the latter the adequate amount of water must be taken or you are ADDING to constipation.
One of those potty stools that can raise the feet, putting the bowel in a better position to evacuate may help a lot for some people.

Miralax daily until the issue resolves, then on a less regular schedule. Drink more water too.