Sure he did--temporarily. And when he finally said, "I want you to help me take my revenge," Frankie was so overcome with relief that he practically wet himself. Then Michael asked him to put his head in the lion's mouth by visiting with his arch-enemies, the Rosatos. As I've posted elsewhere, that was Michael's win-win: If Frankie settled his problems with the Rosatos, it'd be one less thing he'd have to worry about. If the Rosatos attacked Frankie, it'd be one more proof that Roth was behind the Tahoe shooting.
It was Michael at his most manipulative--and one of Pacino's best scenes, IMO.