my mom, age 89, suffering from Dememtia, had a fall apprx. 7 weeks ago and fractured her shoulder. The doctoer prescribed the fentylal patch, after several weeks my mom stopped urinating, to a point where is has to be cath every 3-4 days. My question, could this be the cause, is there any remedy to help her urinate on her own again. Any info would be greatly appreciated.