I am both a swim coach and a physician, and I would venture to say that this is an unanswerable question.
State DMVs and neurologists use certain guidelines to reinstate driving priveledges. but if you shouldn't be driving, you shouldn't be swimming and vice versa.
The main difference would be that with swimming you own self is the only life at risk (as opposed to driving).
The only scientific paper I could find was relating to a study of acute swim stress in mice who were then administered a convulsant medication. Acute swim stress (10 minutes in cold water) raised seizure threshold, whereas repeated swim stress did not affect it.
here is one discussion of that study, and there are several similar studies.
The other common comment about seizures in water is that they can result in rapid submersion of air is expelled from the lungs.
Here is a position statement from a reliable medical publication (Clinics in Sports medicine) about seizures and sports, with a specific section on swimming.
I wish you the best of health, but I believe that anyone who speculates to answer this question is just making uneducated guesses.