Only as a last resort, he/she has a much better chance of survival with her than without her.  It’s much easier to manage it’s care with the mother, if she hasn’t out and out rejected it.
Let me start with and obvious... Make sure you have them in a whelping box that the kittens can’t crawl out of on their own… even at this early age, some are wanderers, and for whatever reason some moms don’t go get them and bring them back.  If that’s not the case, you’ll need to keep a close eye on what’s going on for a couple of days.  Just because he was born first doesn’t mean he was conceived first, if fact it’s more than likely the other way around.  The search and such suck instincts are some of the very last to develop, so even a few days difference in age can affect how efficient he is at nursing.
You’re going to have to supervise his feedings foe a few days, but it’s a whole lot easier than trying to feeding him yourself for the next 3-4 weeks.  
When mom cat goes to feed the others, you act as a sort of “spotter” or personal trainer. Make sure he gets in there on one of the back teats, if he has trouble figuring out what’s what, help him find the nipple by rubbing his nose back and forth against it... He should open up and latch on… if he gets knocked off help him get back on.  In between regular feedings, if mom cat’s resting and willing, try to sneak him in for some individual feeding sessions.  After he’s done eating, move him up to her face to be cleaned, it’s very important that she be helping him eliminate. 
In a few days to a week he should be developmentally and physically strong enough to hold his in the pack, but keep as special eye on him for a while still just to make sure.  Keeping a weight chart is a good way to be sure he’s succeeding. 
Good luck… and keep us updated!

 The answer Dll gave you is very good but in addition to that you can try feeding him a little kitten formula once or twice a day with a dropper to make sure he's getting that little extra he needs.