I'm Doug, and I'm very sorry to hear of your situation. My goal is to provide you with excellent service today.
First of all, some contractors are willing to wait until the close of escrow to be paid, and can even be paid through escrow. However, that agreement would have to be worked out with each contractor individually.
While you don't say it specifically, I will presume that your father is the Trustor and placed the property in the trust prior to his incapacitation, and that the trustee is liquidating the trust per direction of the Trust document.
If the trust is under-capitalized and has no liquid assets, then it is up to the Trustor, or if they choose to assist, to the beneficiaries of the trust to pay for the necessary maintenance of the property, and in this case to provide for the repairs necessary to the sale of the property.
While you as the DPOA cannot be forced to transfer estate funds to the trust in order to make the property salable, there is really nowhere else that the funds can realistically be expected to come from. And it would be in the best interest of the Trust, and it would allow your father's intended purpose for the trust to be fulfilled, were the cash input be made. Finally, if the language of the trust allows for it, the cash input could be provided as a loan to the trust, which would be repaid to the estate on the sale of the property.
You may reply back to me using the Reply link and I will be happy to continue to assist you until I am able to address your concerns, to your satisfaction.
Please remember to rate my service to you so that I can be compensated for helping you.
I wish you and yours the best in 2015,