Hoping he heals him just enough to keep him from dying before he can arrive at a church or clinic where he'll have to pay for lesser healing, bonus points if he leaves the sword in. Realistically he should turn him in at the guild and tell him that he was attacked because the guy wanted to cover up the fact that he tried to kill/abandon him in a dungeon. That would also hit the others that had been in the party at the time and went along with it.
Regardless everyone here and hopefully MC recognize that he's lying and will either try to immediately stab him in the back, or use his sponsors to try to kidnap the girl in the near future to lure MC into a trap. Then it becomes a cliche segue for MC to fight corrupt nobility.