From: Damn Near Dead: An Anthology of Geezer Noir ed. Duane Swierczynski, Busted Flush Press, 2006.
Like most of the protagonists in this anthology, 75-year-old Lionel Dupuy is more than meets the eye. He specializes in killing the elderly to end to their suffering. Calling these jobs "mercies," he uses the alias "Mr. Grimm," a phone voice scrambler, and a dead drop to contact clients and collect his fee.
When someone hires Mr. Grimm to kill Lionel Dupuy, Lionel must figure out which of his sister's children wants him dead. A fun mix of the hitman and detective genres.