What kind of 1911 do you want to build? A G.I. style? Competition? Are we talking a full size 1911 or a Commander size? And what kind of parts did your brother leave you? Colt parts? S&W? It helps if all the parts are from the same manufacturer.
You can find frames (stay far far away from ESSEX frames!) from various sources...just search the net. Expect to pay anywhere from $400 on up for a really nice old Colt frame. You can also find old WWII G.I. frames for a somewhat reasonable price.
A standard full size 1911 isn't all that hard to put together...a gunsmith here has built several G.I. style 1911s...but then again, he's incredibly skilled.
Good luck.
EDIT: I'll add something to what I said about the parts should be from the same manufacturer. That's not quite true. A nice G.I. style 1911 may be put together using slides, barrels, frames, etc. from Colt, Remington Rand, or Ithaca...because those old 1911A1s built for WWII required that the parts be more or less interchangeable without fitting. Ditto for earlier Colts.
We've all seen 1911s with early Colt frames (especially 1918 frames) with later slides and stuff added. They make wonderful shooters.