MTG Salvation

I am posting this for my nephew, who is 14 and understands how to play the game, but hasn't played standard events. He recently was given a fairly decent collection of cards from BFZ through EMN, including some good rares. He has sorted it all but is feeling overwhelmed with building a deck. We have come up with a few different ones that he could build (budget oriented) and wanted some opinions on which one should be built. Please keep in mind we have no way to playtest these beyond ourselves and our LGS standard fnm.

U/R thermo-thing (I think the guy played this because there are 4 TITI and 4 fevered visions)
U/B Eldrazi
R/B eldrazi
G/B sacrifice (we think he was building this, there are 3 westvale in the collection)
W/G humans (super budget, just can't afford some of the expensive key pieces)
W/B life gain/drain AND/OR Treeskadeckaphobia (there are 2 trisk and 4 trees)
U/G emerge (I am not sure if we are missing any key components)
lastly, some sort of G/x eldrazi ramp might actually work.

Some notable rares that are in the collection that aren't mentioned above: a void winnower, 3x sin prodder, an emrakul, 2x kiora (!), a kalitas, an ob nix (PW)

He really doesn't have enough to build R/G werewolves or any sort of zombies or vampires decks. He would have to buy too much for any of those decks and doesn't have the money. And before you start saying to trade, people in my town hate trading stuff. Everyone wants your good stuff for their junk and basically refuses to trade value for value. And the LGS is a small store and doesn't really have too much for trading and buying. So what is everyone's opinions what he should try to put together.

What kinds of decks has he played with so far? What color(s) does he like? How well does he understand the game? Certain decks can have a lot of triggers/interactions to remember and understand.

R/W Aggro running Toolcraft Exemplar Bomat Courier Thraben Inspector Inventor's Apprentice Bone Saw Reckless Bushwhacker - Go from there and build up to higher end or just keep the mana curve down to 1/2 cost spells. (Bushwacker should really be considered based on surge cost). It's pretty straightforward on how to play it.