Thank you for the additional information. I completely understand the problems associated with finding things like large MRI machines as I used to raise Fila's and had the same problems.
If blood work was clear then in all honesty the most likely cause is a brain tumor.
As for trying medication I would suggest at least giving it a shot to see if he holds it down. One thing you could try is the new pill pockets they work great with even hard to pill dogs. I normally give one or two with no pill and then one with the pill so they do not notice. Click here for pill pockets.
Repeated uncontrolled seizures can result in brain damage, elevated body temp that can cause problem with the blood clotting factors, and in many cases they go in to a seizure that does not stop and euthanasia may be the only option.
Would I go through very expensive testing at his age if he were my dog honestly no. The fact that you got him to this age is amazing and a testament to how well you have cared for him.I would however give your vet a call and maybe just get a weeks worth of medication and see if he is able to keep it down and how he does with it then at least you know you tried.
I know how hard it is to let go but if you can not get the seizures to stop that may be the best option. Often in the end letting go is the last act of love and kindness we can show them as much as it hurts.
I hope this helps and I am sorry you have to make this decision. Please reply back if you have additional questions or concerns and I will be happy to continue. If you have no additional questions please remember to provide a rating before exiting the site.