This could be a miracle treatment. Or, unlikely but possible, this could cause every affected cell to have completely junked DNA essentially dooming him to a slow radiation poisoning-like death. Or it could be anything between the two. We don't really have any (ethical) experience in using crispr in humans in vivo and the unintended consequences are unknown. The most likely outcome is that the viral dna is not completely eliminated and this is only a temporary treatment that reduces the need for anti-virals for a time until the virus is able to re-infect previously treated cells.