He'd be a propaganda element most likely, and if any other Stalinists did so, they would too. The thing is, I don't know how far their commitment to the PRC would go, since many of the Stalinists were also staunch Soviet nationalists.
Come the Cultural Revolution, he faces a great danger at being targeted too, even if he doesn't crusade against the revisionists of the Soviet Union. Providing he doesn't help the Maoists, he just lives out the rest of his life like he did OTL.
It should be important to note his indifference to nuclear war, but that would have no bearing on a possible Sino-Soviet conflict, as he would never betray his homeland that much. Perhaps even when negotiations regarding the border conflicts come, he becomes a negotiating player, maybe working with his old comrade Alexei Kosygin. Even then, I doubt the Maoists would let two Russians do their talking.