My biggest concern would be that if you're starting him at lower levels and hoping he'll create a dedicated healer or front-line fighter -- a role that nobody else in the group has opted for -- those two elements will stack poorly. The one-two punch of "please take this role none of the rest of us want to play" and "you don't get the same levels we do" seems like it would say very distinctly that the new player is a second-class citizen, and the other three players are the rockstars.
One or the other is always potentially problematic with a new player. If both is a possibility, I'd definitely bring that concern up to your GM.
Meh, well, it was mostly just a hope. It wouldn't be fair to force him into a role just because none of us took it after all. He seems to be going for an Alchemist.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.