Since you're a developer out of a good university, you will be fine living in the city. I'm assuming you're making at least $100k at the very minimum, and have no dependents. There are still good deals to be had in SF, you just have to know what neighborhoods are overpriced and which are underpriced.
You should be able to get a good-sized studio for under $2500/month, which is a reasonable portion of your salary. If you're cool with roommates, you can get a nicer room in a more convenient part of the city.
If its a big corporation sure, but not at a startup.
That said, he could also live in one of the various co-ops in SoMa for not too much money (if he's fine sharing a room). And the inner-Richmond does have cheap rent as well (~$750-1000 per single room)
Where's the risk if you're getting paid above market? Time was people joined a startup in order to make their equity valuable. If all these funded startups are paying above market a large number of potentially viable ones will go belly up in an implosion of Roaring Teens opulent overspending.
Even though this isn't quite on the topic of Bay Area rent, room and apartment sharing is pretty prevalent in Beijing as well, with similarily ballooning rent prices. Whilst I was living there, I shared an apartment with 3 other people, the landlord and 2 other chinese guys which were sharing their room. In fact, most of the younger foreigners I happend to hang around with shared apartments, and I wouldn't be suprised at some of them sharing rooms either. The only guy under 25 where I'm certain that he had his own flat to live in had a mother who used to work in real estate. Proably the most cramped situation that was described to me by an expat involved a girl that i met in one of the cities posher nightclubs who came to Beijing to find a modeling job, who was sharing an apartment with 5 other girls. Presumably, they did share rooms. And this is foreigners that came to Beijing despite of that. I cannot imagine how cramped some of the BeiPiao (Chinese migrants coming to Beijing) are willing to live just in order to stay in the city.
So if you're young, unmarried and you're not incredibly fussy about living together with other people, I think you should absolutely go for it. Having to share a room isn't some kind of ungodly indignity, especially if you get along with your roommates.
There's a large gulf between sharing flats and sharing rooms though. Sharing flats is common all over the world for obvious reasons, sharing rooms seems like a good time to question why you're in a certain place.
Its fairly common now. I know a lot of people that have rented out their living rooms. And one friend of mine has even rented out the porch (not sure on how that works).
If I were looking again now, I'd check Glen Park, Twin Peaks / Noe Valley, and Inner Richmond. All 3 are pretty close to the happening parts of the city, relatively reasonably priced, and have their own merits. Glen Park is quiet and has Bart access, Twin Peaks has views, Noe Valley is very conveniently next to the Mission and the Castro, and Inner Richmond has some of the best food in the city.
You should be able to get a good-sized studio for under $2500/month, which is a reasonable portion of your salary. If you're cool with roommates, you can get a nicer room in a more convenient part of the city.