I'd push him away from the 300Win and toward something on the 06 or 308 case in a light rifle.
I've been down that road and did not enjoy it. Also went down the tikka road with the same rifle and ended up getting a Montana or 3 eventually anyway, but that's all personal preference.
On the other hand, how well do you like your brother in law? A nice light 300Win and a Leupold 6-18 would be good for a lot of revenge!
