I would continue to work closely with your vet regarding medication and treatment.
However, I would ask for a referral to a veterinary neurologist. From your posts I don’t see that a seizure disorder (indicated by the symptoms you describe) has been ruled out?
Has your vet suggested anticonvulsants? Ask the vet if she thinks a low dose of something would stop the episodes? Do you have a diagnosis? Her problems may not even be GI related? I assume Lyme disease has been ruled out, as that can also cause neurological symptoms.
Maybe you could gate him in a small room (when your out) where there is nothing he can get into, except a bowl of fresh water. Good luck.
