My brother has shingles, when is he most contagious?

See below: Shingles is contagious to people who have not previously had chickenpox, as long as there are new blisters forming and old blisters healing. Similar to chickenpox, the time prior to healing or crusting of the blisters is the contagious stage of shingles. Once all of the blisters are crusted over, the virus can no longer be spread and the contagious period is over.