Does anyone know of a product to eliminate urine odor from upholstery?

the two that I found helpful were
OdorBan comes in a gallon bottle and you dilute it to specific concentrations. It is anything from an air freshener to a sanitizer.
Clorox makes a product caller Urine Remover.
Many people have good luck with Oxi Clean.
Get good protectors for furniture.
Check briefs (tab or pull up "diapers") and change frequently. Best to try to avoid the problem rather than trying to fix it.

Do a search for urine removal on this site, there are lots of them that answer this query.