6 or 7 inches is repairable...you can go to an autoshop or tint shop and they can put a compound in it.
NOTE: it will be repaired (won't crack anymore) but the crack will still be noticeable. also, depending on the location & severity..you may not be able to get a new braketag next time inspection comes up.
Wow, I'm surprised they can fix it once it's reached that length. Good to know
But I don't think it'll impair his vision too much, considering the location:
Then today I noticed that in a completely unrelated area of the windshield, a crack has started at the bottom, dead center passenger side, and runs up at and angle towards the middle... it's about 6 or 7 inches long.