It may close a little more in time, it may close all the way in time, or may not close. What that means is YES you have to be very careful with him b/c there is an opening (hole) without the protection of his skull, thus serious damage could happen if he get hit on his head...
You need to tell you neighbor that both pups have genetic defects and they should NOT breed the parents again
They both should be ok, but you have to give the extra protection as they both are vulnerable.