Another obvious problem is that even if fusion does occur, how do you get substantial energy out past the fluid that is sonoluminescing? Sure the fluid itself can transfer the energy, but while it is doing that, it is largely no longer available for the reaction.
The physicist involved believes this will not be a power source. But it could be an inexpensive source for neutrons that can be used in other applications. It's morew about the science of fusion than about energy production.