The three injections are probably the loading dose and are done fairly close together, that's how mine were done. I then went on to one injection every three months which is what I continue to have. There are slightly different regimes though, depending on various factors.
I have B12 deficiency caused by an underlying medical condition rather than pernicious anaemia as such but the symptoms are the same, and the B12 jabs do the trick. Your friend will be fine and feel a lot better.