Remus didn't think that the patronus charm would cause any sort of harm to Richie if it didn't produce the end result that they hoped for. If anything, it just wouldn't work and they'd be back at square one. No harm done, but a disappointing outcome. Hopefully, it'd do exactly what it did to the dementors and drive it out of Richie. It sounded like the same sort of creature, even if it wasn't of his world.
"Oh, yes," Remus said. "I know him through Eddie, who is friends with my partner." Richie was a bit of a mess, and Remus meant that with fondness. The two of them had a balance similar to his and Sirius' relationship. He regarded them in kindness. "Would you speak with him and then let me know when he'd like to try this?" Remus waved his wand and the wolf darted around them a few times before dissipating back to where it came from.