Father has ms has severe trigeminal neuralgia to the point of not being able to eat. his neurologist has him on med00s not working ideas/places?

Gamma knife: If your dad has maxed out on medical therapy (typically medications such as carbamazepine, oxcarbazepine, gabapentin, phenytoin, baclofen, etc) then he should be referred to a neurosurgeon with expertise in gamma knife surgery. You should be able to locate such a specialist in any major metropolitan area, often affiliated with a university. Good luck; it is a very painful condition.

Maybe could: Find a surgeon who can do a foraminal balloon needle decompression, which is far less invasive. Typically, this can help many and does not require craniotomy, but a newer approach that may be harder to locate. Best luck.