You usually do not treat gamebirds like songbirds! You do not handfeed and water them.
You need to start researching like crazy. Take the fan off of it! Young birds are very susceptable to drafts. You need to buy Chick Starter Crumbles or Gamebird Starter Crumbles, pour them into a very shallow dish(something much(!) shorter than the bird itself). Find a very shallow dish for the water and do the same thing.
Gamebirds, like chickens, do not make noise only when they are hungry or thirsty. Gamebirds do not feed their young, like songbirds, they immediately start teaching the chicks to find their own food. Which is why you can provide "Sam" with food and water and he will eat as he is hungry. He will continue to make noise, because he is alone, and they just do.
Your best bet would to get the bird to a wildlife rehabber. You usually need a license to have gamebirds, which I think the grouse is considered.
-Kim