Yes. It depends on how bad the fall was and how hard your mom hit her head, but it's a definite possibility. Strokes can occur after a significant trauma, usually because a blood vessel gets torn, which is called a dissection. If a fall is bad enough, the lining of a blood vessel can tear and cause the vessel to close, resulting in a stroke. Such strokes usually occur in a delayed fashion, a couple of days or even weeks after the event.

It's important that your mom's doctor know about the fall. It could be completely unrelated to her stroke, but it's still important for the doctor to have that piece of history. A damaged blood vessel would probably heal on its own, but it might require a different medical treatment than a typical stroke.