Since they froze, it's highly likely you'll develop cracks in the batteries and subsequent leaks. If they didn't develop cracks, there is still the high probability that something inside the battery was damaged. At a minimum, as your batteries died, they became heavily sulfated.
Repeated charging with a desulfator 'might' bring them back, but they won't be the same.
As mentioned already, the fix is replacement.
2017 Cedar Creek 38EL/2015 Silverado 3500HD