I am not a lawyer, however in the case of a car crash the deceased's estate is usually sued by the survivors requiring compensation in the event of an at-fault crash. It is my understanding that it is a requirement to sue the at-fault persons before the TAC will pay out their share.
The scenario is kind of different as in this instance, the pilot of the aircraft is 'insured' under the policy of the aeroclub/flying school from whom he is hiring the aircraft.
The owners would certainly be compensated by the insurance company and would only be out of pocket for the excess of their policy.
I am now sure however whether the insurance company then attempts to recover the entire cost of the aircraft from the deceased estate or whether it is classified as an accident which the insurance company covers on their own.
It would be interesting to hear from an insurance lawyer on this one.
Unfortunately I don't think this is a unique case and I would be willing to bet that quite a few fatal accidents in hired aircraft would be cases of suicide.