I haven't seen anything on FIP, but there isn't a lot of non-human animal information.
You should get Jim Humble's "MMS Health Recovery Guidebook".
He has a chapter on Animals.
I got tremendous success with MMS and my cat's FIV.
I've posted about it here and check out my website, link below. (under My Story)
I would think you would get some good results with FIP.
Since FIP is "incurable" and usually fatal, it definitely falls under
might as well try it and hope for the best.
I expect you to get some good results.
If (/When) you do, please come back and tell us.
It helps out others.
Since there is probably a time issue, I hope it works.
(results don't generally happen "immediately" for egregious illnesses)
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mentions, replies to inquiries about, and/or involves a discussion of, the information on my website,
ASpoonfulOfMedicine.com, falls under the Disclaimer on my website.
CHP – The Clean Health Protocol
www.ASpoonfulOfMedicine.com/
You will find info there regarding Jim Humble's "MMS Health Recovery Guidebook".