I am under the impression that seizures result in some form of minor brain damage. Therefor medication is extremely important to prevent further damage. But wrong medication might result in other problems like behavioural and further seizures.
Like a stroke (e.g. TIA) one will have for some time impairment which improves as time passes by. Keep in mind that the boy is young and the brain tends to regenerate (as we learned some years ago), the end result might be more obvious after a month or so. Training though is very important to get the best results. (Wikipedia reference-linkBobath & PNF?)