If he's calling your cell phone you might be able to block the calls. Ask your provider for deatils. Or put this number in your contacts list and assign it the ring tone "no ring". That won't stop the calls but it will keep them from waking you up.
Just received a call from them on my cell. I only have numbers in my phone from people I actually talk to so everyone else is only wasting their time I WILL NOT answer a call that is not from a friend or family member.