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 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.
because a blood vessel gets torn, which is called a
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.