Many fishing rod handles are made from cork. You certainly have to coat it with something but it doesn't have to be CA, as long as it prevents dirt, as GoodTurns mentions, from soaking into the cork then you just wipe it clean. If he wants the spongyness, then CA will ruin that. I'm thinking several coats of something that would soak in and protect the cork, maybe something like Dutch oil; not familiar with all the options. Then after dry for a few days, maybe a thin coating of some type of finish or not, the oil may be all you need.
I've got fishing rods with cork handles that are twenty years old; haven't used them everyday for twenty years but they got a good workout before I got newer rods.