Counselling is your best shot. If he can be persuaded to actively participate he will hear from a "qualified expert" that he needs to do something.

Another thought; don't let him have any. When he's good and hungry he might even listen if that's what he has to do to get some pussy. After all, it's your piece of property so change the rules a little. Politely and gently keep him out until you're ready. Jack him off if necessary rather than let him in early. And extravagant praise when he get's something right will reinforce the message. A bit like teaching a dog or child.

Women have always controlled men with their pussies, and you can do the same.