Robyn,I am so glad the little guy is home and I bet so are you,a dog/cat can live with seizures,on medication,but if there is something else going on,I hope it's something curable
I know 14+tiny little Poodle gets seizures and has for her whole life,if I remember right she's now about 14yrs old.
I know nothing about dog-food,but like Breeze said,the right supplements might let you feed him the food he's used to,not the crappy Medi-cal.