If cryonics works, [family and friends] still suffer the same [grief].

Wrong alief. Despite saying "if cryonics works" the author in the rest of the sentence still expects that it does not.

I disagree with this conclusion. The validity of the statement depends on the beliefs of the family and friends, not the beliefs of the author of the sentence or the individual being frozen. For average values of family and friends, it's probably even true.