Is there any written agreement between the buyer and your mom?
Was the SAP signed?

Ya, hell notes are relatively cheap.
The transfer method is also convenient, you just need to burn them.


If the agreement between a seller and buyer is broken, the law will come into effect.
The money was taken from the buyer, not the buyer's relative.
If the buyer come back alive and ask for the money and he want to proceed the sales after you paid the money, what do you think will happen?