That amount of water over that amount of time is beyond "should be fixed". There will be rotten wood under the roof surface that needs to be found, cut away and replaced, which is a bother and an expense (we increased our expense by using marine grade plywood when we did our roof last year, hoping it will outlive us) but if not done the entire structure is in danger. It sucks, but your Mom could end up losing her investment if the roof caves in.
(no subject)