Does a very, very foul rotting odor from urine indicate a UTI? MIL (88) has had several UTIs in the past couple years.

We realize eventually that it is a UTI by the confusion. She has confusion now, but the odor is absolutely horrible, and she has dribbled her underpants. If you have ever smelled the air let out of a tire innertube, that's the smell. I do her laundry at my home and the smell permeated my laundry room. Also, has had only 3 BM's in last 6 weeks. Very lethargic, seems like her brain's needle gets stuck in the evening. Will call 20 times, say the same thing and hang up. Sat in her walker in the middle of the LR for 2 hrs. the other night just looking around.
We have a camera in her apt. We are basically her assisted living.