From the linked article,
Studies suggest that as you get older, your brain shrinks and pulls away from the dura, especially after you're 60 or 70 years old. But the veins keep holding on to both the dura and the brain. So as your brain pulls away, some of those veins become more exposed and more vulnerable.
Researchers say if you simply bump your head on the eaves of your attic, as Arling did, or if you simply start to fall and then catch yourself — so your head doesn't strike anything, but it jerks in the air — that can be enough force to jostle your shrinking brain.
I have atrial fibrillation and was warned about the danger of using blood thinners like Coumadin... that is the primary risk to be aware of. It seems to me that Illary had a life threatening clot in 2011 related to a fall that was close to producing that type of bleeding.
For that reason I do not take Coumadin but rely upon Nattokinase, which is a natural blood thinner that does not have the same dangerous side effects of other thinners. Seems like that option is too little too late for Illary.