Check the guides at the top of the page on VisaJourney. It's basically a flowchart on what to do and when to do it. The guides also have HOW to do it, too.
A lack of residence isn't a problem as long as you can put his parents down on the forms AND they are willing to co-sponsor. To co-sponsor for a K visa, the person in question must make 125% of the poverty level for thaty household size, e.g. if the household was your parents and the two of you, you have a household size of four. You will need a co-sponsor to get the visa if you as the US citizen don't have a US based job or ginormous savings account, anyway.
You can get a temporary EAD (good for 90 days) stamped in as long as you come through JFK airport, then it's just the matter of getting the social security card, which takes 5 to upwards of ten weeks. If he's in the system when you go to apply, you'll be on the short end of that time frame. If he isn't, then it will have to be manually verified and that takes some time. We waited ten weeks for manual verification and there was no sign.
The temporary EAD is almost useless...it's good for 90 days only and will in all likelihood expire before he gets his SS#. If that happens when he has a job he has to stop working until the EAD is issued or you successfully adjust status (get the green card).
If you don't come through JFK, then you have to apply for the EAD. That can take a few months or longer, but I don't know too much about that because in our case it wasn't necessary.
US immigration is a very BIG maze to naviage through!