Are you sure you guys don't have a "casualty" tax deduction? In the states, you can file
Form 4684 (Casualties and Thefts) to account for losses from any kind of act of God, hack, theft, etc. where you lost bitcoins. There are some limitations, though.
This is the breakdown for a "tragic boating accident" sort of tax deduction in the US:
I've burnt everything the tax man has ever sent me unopened so wouldn't have a clue, but I've never heard of anyone talking about something like that. If it were that easy everyone would be saying their bank account caught fire when it was time the pay the tax bill.
The tax man don't give a shit you don't have the money now. It's your responsibility to have kept it back.