It will work on him eventually when he is able to be Ascended.
I purchased a 4-5 Ascension crystal from the Meta store. I then looked to see other option and I had options to trade for heart of fire gems. I purchased all of the heart of fire gems. When I was ready to r5 my R4 champ, the 4-5 was gone? Did I trade the 4-5 bsck for the 3 heart of fire gems? Why was that even possible after a trade was already made?
Looks like there's an offer to trade a 4-5 gem for 10% of a T5A (which, holy cow, what an absolute joke of an offer; "Did you want to trade this restricted rank-up gem for 1/30th of the Alphas needed to R5 someone else, not even factoring the T4A, T7B or class catalysts you'd also be saving by using the gem?"). Did you somehow buy that instead?
It's trading the exchange token for the t5a. Not trading a 4-5
There is an option to trade a r5 gem for 6300 t5a fragments
There are two trade-ins. The first is under the Trade-In Gem Bundles and offers 12600 T5A fragments in exchange for the Trade-In Gem. The other one is under the "Ascension Rug Exchange" section. That one allows you to trade an Ascendable Champion 4→5 rank-up gem for 6300 T5A fragments. Either one is still a bad trade. An r5 rank-up gem is saving you three T5A, four T7B, six T4A and seven T6CC. It can only be used on Ascendable champs, but that's still a lot of material that you would effectively trading for 10-20% of a single T5 alpha. T5A isn't so rare that it's worth trading all of that other stuff for it.