Darrin Drader
Explorer
If you are reading this post, you are investing mindshare in the Darrin Drader corporation. As the spokesman and president of the Darrin Drader corporation, we officially do not espouse, sympathize with, or condone kicking people in the junk and burning their house down.
On to the matter at hand. If you want the archer to stick around, you, as the DM, need to show enough leadership to get the rest of the players to stop ganging up on the archer. While in-party fighting seems to be in vogue throughout gaming groups everywhere at the moment, it is up to you to keep it from happening to one person so much that they feel alienated from the group unless that is the type of game you want to be running. All you have to do is tell the rest of the group that you aren't going to allow this anymore, and the next time it happens, just refuse to allow them to do it.
On to the matter at hand. If you want the archer to stick around, you, as the DM, need to show enough leadership to get the rest of the players to stop ganging up on the archer. While in-party fighting seems to be in vogue throughout gaming groups everywhere at the moment, it is up to you to keep it from happening to one person so much that they feel alienated from the group unless that is the type of game you want to be running. All you have to do is tell the rest of the group that you aren't going to allow this anymore, and the next time it happens, just refuse to allow them to do it.