+1 to don't get rid of any guns, get rid of the brother.
Seriously, if you absolutely had to (pay off debt, etc.), the only (semi)-redundant ones that I would be willing to get rid of would be the .270 Weatherby mag, and the .22 WMR. The .270 has each extreme covered by the .270 Win, and the .300 Win mag. The .22 WMR has each extreme covered by .22lr, and .223 Rem.
So those 2 cartridges do the work that one of the others does just as good. You'd just have to decide if (for the job at hand) you'd rather have a little more power, or a little less power.
Also depending on what guns the shotguns are, possibly redundant there as well. If ones a SD, and the other is sporting, you need'em both. If they're both SD or both sporting, they do the same thing, equally as well.
But first, I'd start with filling in the holes. First fill in the hole in your brother's head, then fill in the holes in your cartridge selection.
Wyman