I bought a brand new battery for my car before my accident and I made the stupid mistake of just letting it sit there for four months so that was a gonna & I have a couple of leisure batteries I managed to wreck after not a huge amount of time so if this works it could be a good thing.
Sorry to hear about your accident.
Battery sulphation occurs when a battery is left flat for a long period of time. If the sulphation is new and 'soft' then higher voltage charging can help. But soft sulphation occurs with normal everyday battery use and charging removes it anyway. It's how a battery works. But once the sulphation has hardened on the plates its impossible to revive the battery.
If there is a mixture of hard and soft sulphate on the plates then a high charging voltage can help with the soft but not the hard. In many cases it could be just enough to revive the battery enough to start the engine. But the capacity of the battery will be reduced and probably won't last long.
Personally I wouldn't fork out for a battery charger that the manufacturers claim will do this. The C-Tek one is expensive and you have no guarantee that it will work. I would replace the batteries now.
If you have a sealed maintenance free battery it should never be recharged at a voltage higher than 14.2v due to gassing. Recharging it at 15 + volts isn't recommended.