Firslty, with regard to the property transaction there has always been a duty over the purchaser to inquire about the property.
Secondly, as iif something goes wrong then he can save himself. But, it is not necessary for him for detail inquiry so as to he is not bound to go the registrar and cheque the property details.
Thirdly, if you can prove that mother inquire then it would be good for you.
Fourthly, as you have paid in sach you
Can also be questioned about your income sources.
Fifthly, but yes don’t worry about that false allegations if you know the the signatures are genuine.