My 13 year old Jack Russell has suddenly started with grand mal seizures. On meds now and only focal seizures?

One vet told me Epilepsy that's likely been missed before now. Another vet told me he may have brain lesion. Does this sound like distemper?? Since seizures started (a cluster of 5 grand mals), his gait and posture is periodically odd. He will stand with back paws touching at times. He was started on prednisone in hospital as a precaution and I'm about to taper him off of it. I'll love any feedback based on experiences or similar cirstances. He has arthritis, cataracts and moderate hearing loss. Other than aging issues, negative medical history before now.