He did send his son to Dumbledore's maw, the one he believes burned alive his wife for no reason. I don't think sending him back with Harrymort there would bother him that much. It's not like Harrymort has anything to gain by killing Draco. The danger comes more from Hermione than from Harrymort, and it seems that she's scared enough so she'll never attempt anything against Draco. And Draco will be on guard. So... I think Draco will go back to Hogwarts.