If you doubt the prophecy because the disease was not directly named AIDS, how about the incredible prophecies that He revealed which are very specific, such as babies with three eyes, human being giving birth to babies with horns, human being giving birth to kitten, and cat giving birth to human being? When, not if, these happen, will you believe?
This is too much of an open-ended, vague prediction. It's open to interpretation, or just too open-ended.
Three-eyed babies and babies with horns -- the odds of a baby being born with three eyes, somewhere at some time, are actually not that bad at all -- birth defects happen (
in about 3-4 times out of 100, according to Sci-Tech). Same for a birth defect, a deformation of the skull, that might resemble horns.
Woman --> kitten or Cat --> human - I highly doubt that a human being will /ever/ give birth to a kitten, but children are born with cleft lips all the time that could make them look like they have cat mouths; if you mean that a human will give birth to an actual kitten (and that kitten will be verified as a member of the felis cattus species), that's one thing. But prophesies such as this are notorious for being "cherry-picked" later (such as the cleft lip thing). Same thing with cat --> human; I imagine that at some point, a cat somewhere will give birth to a deformed kitten that /looks/ vaguely human (especially among humans who are uniquely hardwired to find human faces in /everything/). If your spirit is claiming that the human will be an actual /homo sapiens/ coming out of a cat (poor kitty!), that's one thing. But I rather suspect anything even slightly human in its appearance will be called as a "hit".
So you have to be much, /much/ more specific in your predictions. You have to say, "a woman will give birth to a kitten, and by 'kitten' I mean actual 'felis cattus', not a human child with a birth defect, on XXX date in YYY place." Or "on such and such a date, in such and such a place, a human child will be born with horns on its forehead that will be indistinguishable from goat horns, and will be found by doctors to be of the same physiology as goat horns and not a birth defect simply resembling horns."
Your prediction can't be subject to interpretation or explanation ("it looks like horns" -- "the kid looks like a kitten") -- it has to be self-evident.
Also, an open-ended prediction (that is, no date given) cannot, by its nature, be disproved, because it has no expiration date. I highly doubt that JREF will accept a prediction of this type for their Challenge.
Summary: in order for a prediction to be acceptable it will have to be:
1) not subject to any kind of interpretation or explanation at all (i.e., be very specific)
2) have an expiration date
3) be verifiably falsifiable (i.e., JREF will be able to determine whether it happened or didn't)