if you are willing to exchange/refund via the lemon law (at least, this is a law in NY, not sure about your area), i would be direct and upfront. Get a quote for an indepth exam from a local herp vet, then call Ken and say 'This is going to cost me XXX$ to figure out; what i propose is either an exchange (for another dum, similar value snake, or money), or are you willing to reimburse me the value of the snake, should it be something serious like IBD, or a genetic issue where you would need to contact the sibling's owners.'
Make it clear about what you are asking, what you are planning to do, etc. Start calling around local vets now, and ask how much an initial exam for a snake with neuro issues, that way you can compare cost/find out who knows herps well, etc.
Sorry, best of luck
hope things work out.
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