AFIK he didn't modify the garage, so once it's time to sell all he has to do is drain it, disassemble it and no one will be the wiser. House insurance doesn't

AFIK he didn't modify the garage, so once it's time to sell all he has to do is drain it, disassemble it and no one will be the wiser. House insurance doesn't necessarily extend to a free standing garage, so he might be cleared there too, he just has to hope nothing disastrous happens to it.