Well, that one isn't going to be so easy.

One of the greatest concerns here might be in the positioning relationship of the loading for the gasket fire-ring versus the cylinder head bolt hole with the crack separating the two. This is a high stress area, where when assembled, the bolt hole is being pulled up with several tons of pressure, while the gasket fire-ring trapped between head and block deck is loading the top of the cylinder column effectively trying to push it down, and is probably the cause of this crack in between.
What this means is that the repair is going to have to result in a sum of structural soundness that surpasses what was there before; and this isn't going to be achieved with solely a "cold-repair", and although I don't see any other option beyond welding as being prudent, but it in itself comes with limitations and drawbacks, even when executed by a capable individual.
And yes, a sleeve (or two) will probably also be required, if the repair effort gets that far.

B.T.W. What is the blocks' current bore size, as it probably will require to be something greater after the initial crack repair process so if it's already out near its' limit then . . . . . ?

Scott.