Start by checking to make sure that her diapers or incontinence briefs fit her well and aren't leaking. Where does she put the used diapers or briefs after they're soiled?
If she hasn't yet bought one, you should recommend that she buy a special bin for soiled diapers, like the one you would use for a baby's diapers; this keeps odor from seeping out.
You should also check to see if your mother has had accidents. Vinegar and water with a little elbow grease can lift the smell out of upholstered furniture or bedding. Clean her carpets or get them professionally cleaned. Find out, too, if she's letting soiled laundry sit around. She should also use a covered clothes hamper.
If she's willing, your mother can take an oral supplement that reduces or eliminates odor by deodorizing urine. It's called chlorophyllin copper complex and it's probably available at your local health food store. But check first with your mother's doctor to find out if it's safe for her. Anyone taking blood thinners or antibiotics, or anyone with kidney failure, shouldn't take it.