Payment through payorder

A friend of mine has his property being sold through an estate agent. The buyer has given payment of 10% advance. Now for the rest buyer has made a payorder and shared its image on whatsapp. However buyer is not giving payorder in advance but will be giving it over on the same day as we go in front of registrar to sign the sale deed. So buyer will give payorder and then ask to sign sale deed same day. Payorder when submitted takes the end of next day to transfer to bank. Please advise if it is safe to take payorder and sign the sale deed and transfer to buyer.

Thanking you