[Wylie's Mom]

I was going to mention reflux bc these symptoms can indicate it....and reflux can especially happen in the middle of the night when laying down, and throat is relaxed. But is this a puppy? Reflux isn't impossible w/ a puppy, but it'd be a little rare. Unless something is bothering their tummy pretty bad.

Sounds like he is throwing up bile...bile is usually yellow tinted, but can be clear too. Throwing up bile is another sign of tummy irritation. Have you tried giving him a mild treat before sleep, just to absorb any possible icky juices? Like a little blob of white bread maybe.