I am not so sure. Commenting on how Sonny ran the olive oil business, Vito told Tom that he thought "Santino was a bad don, rest in peace." Had Sonny lived, and had Vito made the peace by allowing drug sales to take lace albeit with some restrictions, I think he would have resented Vito because in effect Vito was now going along with the drug business....something which Sonny thought was a good idea all along. From his point of view, had the Corleones made this deal with Sollozzo, the assassination attempt on Vito would not have happened, and the war he had fought after it would have been meaningless. Moreover, Michael who was now "with" Vito, had tasted blood, had lived in Sicily, and had abandoned any hope of living a "legitimate" life. If he came into the family business in any capacity, I would see serious arguments between him and Sonny, and eventually when Vito died, this rift could have had a significant effect on the future of the family.