I have never known a cat not to think brewer’s yeast was the tastiest substance on earth. It is very high in B vitamins so I wouldn’t recommend indiscriminately adding it to any cat food you serve your cat unless the vet says it is okay to do so; you wouldn’t want your kitty to OD on it. However, if the vet agrees it is okay to offer to you cat, I’d try putting a sprinkle onto his food and see if that increases its appeal.
I don’t know if real brewer’s yeast is still available any more since “nutritional yeast” is usually what is for sale. My current cats like nutritional yeast too, but I don’t know if there is something special about the brewer’s - it seems to drive cats especially crazy.