270 Weatherby ? and ? for Rocky

[Jack]

The Trophy Bonded Bear Claw is a tougher bullet than the other 2.
My opinion is that your brother in law has enough gun, but he probably didn't have an appropriate bullet before.
Were it me, I'd load the Winchester Fail Safe, Nosler Partition, Speer Grand Slam or a Barnes X bullet. All of those are proven large game bullets and would be good choices for elk.
And, you're right, a 140 or 150 would probably be the right weight bullet to look for.