If you were allowing one player a race built with 13 RP, would you give the other PCs any sort of boon to help adjust for that, or is 13 close enough to 10 that it won't make much difference?
it depends on how concerned your PCs are with balance or 'equality'...
even a 10 RP race will be superior to a base race when its designed with a specific build in mind, and you can put together a fairly formidable race with 13 RP (for example a half-giant that's large, with reach, and gets +8 Str). if your PCs are satisfied with their characters and will not feel threatened by or competitive with the new race then just allow it. if that won't be the case then think seriously about asking the other player to either play a base race or come up with a new concept.
if you really want to accommodate him, i'd suggest asking him what kind of race he's interested in and then build it yourself. that way you can integrate it into your campaign and make sure that its a race that could work for a variety of classes (and capable of building a society), instead of just an excuse for one character to be extra powerful. even then that character will most likely be a little more powerful than the others so it might not be a bad idea to let the other players pick (or assign them) an extra 1 (or maybe 2, for weaker races) RP trait.
Thanks.