I too fail to see how the numbers make this a profitable buy and hold.
One number that's missing from your story is how much it's worth - or how much you think it could sell for. You said he wants 420k. That's nice - is the place valued at 350k or is it valued at 580k?
I'm going to make a huge assumption and say that what he wants is probably either well above - or close to - market value. I'm not getting the vibe that there's a lot of meat on this deal. Lets say though - If you DID "put together a team of investors" and rehabbed it, what's your ARV?
What the #$%& kind of realtor takes over a week to do a comp analysis and come up with a suggested list price? Your buddy wants to sell yesterday yet he's willing to wait a week for something that an assistant can pull together in no time at all? Pfffft.
Since you don't want to buy it (which is confusing in and of itself considering the title of this thread) why don't you convince your friend to give you 3 weeks to get licensed. Take an online course, take the test, get your license - you'll pay 2.5-3k out of pocket and the day you are licensed - bam! you get your first listing. You sell it at his desired sales price of 420k, at a 2.5% commission rate, minus the brokers fees and you'll clear enough to cover the cost of your license, pocket a couple grand, and you've broken into RE. Win win. It's like wholesaling but... not. ;)