Terribly sorry to hear about your brother.

Buy it. Then buy a scope you've always wanted and shoot the hound out of it.
A buddy has one of the .257 Vanguards and it's a laser.
Yes, smaller stuff will eventually beat it in terms of trajectory and drift, but not for sheer unadulterated speed. I like the idea of a 6.5 Creedmore, and I want one, but you'll never boast of 3300-3400fps with a Creedmore.
These days, methinks if I had one I'd be tempted to reach for 110 accubonds and RL 26 for my first move, go forth and smite all things in my domain that need smiting.
I have a .25-06. I love my .25-06. I've had it for 20 years and it's not going anywhere. But sometimes, at night, I can hear it crying in the safe, wishing it was a .257 Weatherby.