Like you, I have looked after a large number of cats and kittens and plenty of them from very bad situations. The raspy voice and gummed up eyes make me concerned that this kitten could have the calici virus (one type of URI). Of course, I don't know, but I've had a few cats with that particular virus and the raspy voice and really bad eyes were what I remember well. Calici is a pretty bad URI virus, and very contagious. Please remember to use a hand sanitizer after you have been with Val. Calici is the URI virus, if I remember correctly, that can mutate into FIP. And, it can cause blindness. I hope you can get Val on antibiotics as soon as possible. In the meantime, put him in the bathroom with you whenever you take a shower because the steam will help him. Just don't let him get cold right after. Bathe his eyes with warm water whenever you can.

Good luck with Val! With some extra care he will pull through this and become a great companion to both you and Merrick.