Hey there,
I don't breed bettas but I do breed budgies and physical traits are highly hereditary so I would say that it is the same with bettas which is why people choose breeders based on physical characteristicts that they like or are desirable for showing purposes. Breeding your fish to a female with good strong rays may improve the quality of the offspring and later if you breed with babies from this spawn then as long as you continue to breed to good strong rayed fish I think it would be likely that you could breed out the crumpled fin look though it may takes several generations. I am not sure how long as I am not really up with bettas genetics, I like to keep nice quality fish but I don't have the time to breed them so I just keep them as pets

Goodluck with whatever you decide though, he is a lovely fish.