Noble intentions without a doubt.
How will you introduce him to the escort? Will you give him any warning time for him to get ready?
however you want approach this the moment you tell an escort "I would like to hire you to have sex with a friend of mine" he'll think you're 99% likely to flake on him.
the moment he walks out of your friend's place unpaid he'll think he got screwed the wrong gay. Just make plans with him, tell your friend your plan so he's horny and ready to have sex, and pay the escort the moment he meets your friend.
Bingo!