Have you a belief in a higher power? This bird may be in your life and YOU in his, for a reason.
While the bird may benefit from meds, you may benefit from the bird. With seizures from an unknown etiology such as yours, until medical research takes that next step ahead to figure you out. Meanwhile, there is something soothing and grounding about letting an animal into your heart - and more so when that animal is similarly 'disabled' (differently abled) as you are.
Give him every chance - just like you'd want.
Until then, offer his food and water at the bottom of the cage - in shallow, wide dishes rather than deeper bowls. Be sure the perches are nowhere above the dishes and even so, be sure they are meticulously clean throughout the day.
Lower his perches to just enough above the bottom so that his tail has plenty of clearance and not dragging on bottom. This way if he falls, he won't get hurt and can recover quickly. With larger, wider dishes to eat and drink from - he just has to get into the general area of food/water and he'll succeed.
Note: Make sure the water dish doesn't hold water high enough to reach his 'knees' (which are actually 'elbows' ). In case he falls in he won't drown. However, if he has a seizure near or in this or any water source that's a threat so watch over him carefully during the day. At night he shouldn't be doing anything but sleeping. Keep an ear out anyway
This bird and you may be made for each other. And again, I will support you BOTH all the way