My mother in-law suffered from arthritis (or joint pain --- she called it arthritis but I suspect it was really joint pain from autoimmune issues which she didn't get diagnosed until several years later). She took a LOT of ibuprofen and started each morning off by taking it on an empty stomach. A few years later, she was in the hospital from a bleeding ulcer from which she almost died. Now she is not allowed to take ibuprofen any longer and has very little choice among pain meds that will work on her that she can safely take (longer story).
So in short - don't ever take ibuprofen with any consistency on an empty stomach - ever. She should definitely arrange her eating schedule with her need to take ibuprofen.