I was a Zookeeper (mammal department for a major Zoo) for 15+ yrs, & am also a Vet Tech. Have raised multiple white tail deer fawns (plus many other animals!!!).
Unfortunately people think fawns are "abandoned" all the time, and 99% of the time, they are *NOT*, Mom is nearby. But what's done is done, and I don't know if she will come back or not, altho often they do. Depends on how long baby has been gone, and how maternal/experienced a Mom she is.
Does baby still have dried umbilical cord on it? May only be a couple days old. Fawns are usually pretty passive about being handled when they are very young, so the "no fight in it" does not nesc. mean a health problem or weakness.
As far as diet goes, my advice is let the pros figure out what formula they want to use. Are several options that WORK, but some are DEFINITELY more optimal (!!) Also, feeding method may depend on if it is to be re-released into the wild, or kept in captivity with humans. They also absolutely *SHOULD* be stimulated to "potty" when they are very young.
Is there an emergency 24 hr veterinary clinic in your area that you can call? They may be familiar with local wildlife rehab center's protocol, or even be able to house it overnight & turn it over to rehab. At the VERY LEAST they should be able to advise you on what to do, feed, etc., for tonight. (!!!!!)
Sorry not more specific, but I hesitate because I am not there to see/evaluate it.
Edited to add: oop, just saw that original post was HOURS ago, so my advice is probably a moot point/too late.
sorry!! please DO let us know what happens with the little guy if you have a chance, tho...