Two teenagers in a coma meet in a transition state in the afterlife and discover they’re soulmates with a decision to make on whether or not to return to their prior lives.

Very neat idea.
Feels a bit wordy.

Would it work for your story to clarify one of the teens as the MC?
I don't know your story like you do, but could something like this work?

When a teen falls into a coma and meets her soulmate, she must convince him to fight for his life or choose between her own life and following him into the light.

Mine is too wordy, as well, but I hope it helps.