It is a standard action to administer a healing potion to an adjacent player, even an unconscious one. This will allow the fallen PC to pop back up. Its not much worse than a heal check (also a standard that required adjacency) in that it may (or may not) cost a minor to pull the potion, but at least its a RAW option.

My real suggestion though is to have one of your characters MC healer. Its a bit of a feat investment, but in this party it is sorely needed. It is a fairly limited solution, but if your other characters have some personal healing effects (also a must in this situation) it can be saved for such a moment when a comrade has fallen and it is inconvenient to try another solution.

It is a standard action to administer a healing potion to an adjacent player, even an unconscious one. This will allow the fallen PC to pop back up. Its not much worse than a heal check (also a standard that required adjacency) in that it may (or may not) cost a minor to pull the potion, but at least its a RAW option.

You can also expend a standard action to make a DC 10 heal check to allow a character to expend their second wind (they don't have to be unconscious).

My real suggestion though is to have one of your characters MC healer. Its a bit of a feat investment, but in this party it is sorely needed. It is a fairly limited solution, but if your other characters have some personal healing effects (also a must in this situation) it can be saved for such a moment when a comrade has fallen and it is inconvenient to try another solution.