No.
You can contact him yourself but there is no way to prove that a money order has been purchased or sent, so he will just have to trust you.
And you will have to trust him that he will admit the MO has been recieved and that he will send the purchase.
All of which can take over a month.
If the seller demanded a money order, keep this post handy for the "I told you so" responses. Money order payments are one reason most sellers and buyers use Paypal or other electronically traceable methods of payment.