If your DM allows Unearthed Arcana, there is a ritual the Cleric can cast called Ceremony, choosing the Investiture option, you can allow a willing humanoid to cast a 1st-level spell that you pay the slot for:
You perform one of several religious ceremonies. When you cast the spell, choose one of the following ceremonies, the target of which must be within 10 feet of you throughout the casting.
Investiture. You touch one willing humanoid. Choose one 1st-level spell you have prepared and expend a spell-slot and any material components as if you were casting that spell. The spell has no effect. Instead, the target can cast this spell once without having to expend a spell slot or use material components. If the target doesn't cast the spell within 1 hour, the invested slot is lost.
Of course, this is only a temporary solution, used for contingencies for when you foresee yourself getting knocked unconscious within the next hour. For a more permanent solution, have your friend pick up a feat or multi-class into Cleric, if he can.