I assume you mean the pad, since you described it as brittle.
Yes, a crack in the dash pad can be repaired, but unless it is in a vey inconspicuous place, it will show. My 68 dash was brittle and cracking on both ends right at the top. The more I tried to repair it, the more cracks grew and showed. Last year when I had some interior work done, I decided it was time to replace it.
I'm going to let some of the guys that do multiple restorations tell you where to buy....
Good luck in whatever you decide!