I would generally want more information than the small amount provided in the OP. However, as I absolutely love the idea of this, I would probably do something like the following:
Wisdom or Charisma + Religion. Sliding DC affects the nature of the result:
10 or less: You get an answer...from a god you hate, not the one you asked for. You will owe this deity and they WILL call that favor in a situation you won't like or work toward converting you to their beliefs.
11-15: Either a neutral third-party deity answers, and offers a hard but fair bargain, or the deity you wanted answers, but demands a very high price (in your eyes; the deity might see it differently.)
16-20: The deity you wanted answers, or one of their close allies, and gives you a reasonably fair bargain for their aid.
20+: The deity you wanted answers, and is surprisingly favorable to helping you, though you would earn their gratitude if you returned the favor and did something beneficial for them in return.
Even with a bad roll, you have the possibility of getting what you want...but will the benefit be worth the price? Will a day come when you and/or your friend look back upon it and think it would have been preferable to die to those injuries? This is a potential campaign-defining moment, something from which incredible stories may spring. I am 100% for supporting such things. Indeed, I find it very disappointing that so many folks here choose to respond to it with either outright rejection, effective rejection, or (worst of all) "well guess you should have played Cleric/Paladin, my guy!" This is a player giving you a GOLDEN opportunity to make their lives more interesting, more adventurous, more uncertain, more difficult. Squashing that enthusiasm with "welp, sucks to be you" or "hahahahahaha no, hell no, and never darken my door again" is just...sad.
Our hobby is open-ended. It's such a shame so many folks take it as an invitation to close off the vast majority of possibilities.