This is the only part that matters.

Any expanding bullet is fine. If he's hunting coyotes for depredation control, then I'd look at something that expands in a big way, that way if it's not a perfect hit, it blows a big d@mn hole. V-max, Nosler BT, SGK/SMK, etc.

If he decides "messy" isn't his way, then the Hornady A-Max, SST, Interbond, Nosler accubond or partition, etc. Idea here is wasting energy. Harder bullets expand less, exit with more energy, and make less of a mess.

He may not stabilize lightweight bullets well, and they most likely won't be any less messy than the tougher built, "standard weight" bullets.

Don't put quite as much powder underneath them and they'll get a bit nicer on clean up also.