My Lady has had epilepsy since I adopted her at age four. That could be what your foster has.
What kind of neurological problems does he have? The seizures might be related.
As long as he is coming out of seizures, don't worry that you can't get him to the vet today. There really isn't anything that can be done.
This website has been my "bible" for dealing with Lady's epilepsy:
Canine epilepsy and diseases that cause seizures in dogs