Tony Crosland lives?

I've always thought it a shame that Tony Crosland never saw the rise of New Labour; it would have been interesting to see his reaction.

But, say his 1977 stroke is ignored and he lives on; where can his own career go from there? There were rumours at him being moved to the Treasury, and from there a possible successor to Callaghan. How would he have reacted to the SDP?