It is best not to purchase puppies with joint problems. You can help your breeder by pointing out your observations. I have not heard of this in German shepherds. The vet put him on Phenobarbital, 30mg twice a day . He still has as many as 4 episodes in a 24 hr period.
Nobody seems to have a cure.
He is in good health otherwise, has no liver damage, no kidney problems, etc. The breeder that I got him from has passed away and I can't get any info. He sometimes goes months without one at all. I love my dog and I want to do what I can to keep him. Epilepsy can be caused by metabolic diseases, such as liver problems, or from damaged brain cells.