How is he doing? My beardie did this once before i can't seem to find the article but all i did was keep her slated downwards to drain the water and mucus and to keep her above her basking light to keep her warm. When i was doing that she was very weak and didn't want to fight back too much. But sometimes she wouldn't fight back and just fall asleep and i freaked out cause i thought she died. When this or if this happens don't freak out and give up because it might not be too late,flip her over on her back (this isn't good to do to your beardie) but flip her over and see if she would fight back, If he does then hes fighting mine did this many tines but then after awhile the mucus and water mostly all drained and she got her energy back. I held her up too her light again to make sure she was really warm as if she was basking because just in case she didn't want to bask later on or something.
this is more of a thing to do if he was drowning
Since he wants water he might be dehydrated so maybe instead of putting him in the
bath for at least right now have him dink water from a eyedropper so he would drink slower and not get to much water that he cant handal. Just take the eyedropper and squeeze a few drops on his mouth he might start to try to drink if he does then squirt a few water droplets on his tongue when he takes it out to drink.
I hope this helps somewhat. Hopefully someone will help you further if you need it.