My mother was suffering from arthritis and had difficulty walking until she started taking Celebrex. She became more mobile, was happier and enjoyed life again. When she stopped taking it, after a week or so she stiffened up and is hobbling along. Hope they find that Celebrex is ok. Advil is not doing the trick.
Check the Celebrex study; if memory serves, it was done using terminal cancer patients at 4 to 8 times the recommended dosage, and almost anything can cause problem when taken at high dosages.
Other studies have indicated a reduction of certain heart related issues -- apparently due to the anti-inflammatory characteristics.
Your mother might want to discuss the issue with her doctor.