Seizure/Blood clot in brain

Hi, my mother has dementia which started quite young and she has a bad seizure 2 weeks ago.  She had never had anything like that before. Several months ago her doctor told us she had a blood clot in her brain but that it was "no big deal".  She was taken to the hosptial and they are working on her medications now for seizures, but we have since heard from several medical people (doctors, nurses, interns) that the clot might actually have caused the seizure?  Has anyone had any experience with this?  Thanks!