There is no “wake spell” or “counterspell”. There is an action to wake up adjacent character. Characters on 2 levels of height difference or above are not adjacent, even if they share seemingly adjacent tiles.
That said, I think for that very same reason sleep spell should not affect characters on 2 levels of height difference or above, it seems like a oversight on the part of developers.
As for your screenshot, your positioning is extremely poor and what ever damage you take, it’s well deserved. You shouldn’t place your characters next to each other in that fight. They should always end between 1-2 tiles apart. That way one enemy can put asleep only one of your characters, and your characters can always wake up one another. That way you are 100% safe as long as at last one of your characters is awake at the start of your turn.
Albs are quit easy once you understand how they operate. The critical part is to survive first turn when you are grouped together. Spreading during pre-positioning on the world map helps with that to some extend.
It also seems that high resolve can resist sleep spell, although I am not sure about it. In case it does, having a sergeant with high resolve should give you upper hand.
