Clark, I think you might find that the testing required to certify a boron or carbon patch to an existing crack might be a trifle pricey.
There is also the question of changing the loading distribution in the forging that could cause cracking elsewhere or even ending up with a structure “too rigid” that ends up over stressing the wing attachment points on the wing spar.
However, I am at least 20 years behind the times and I defer to real Aviation structural engineering professionals.