You are absolutely, positively doing the right thing. He has to be uncomfortable. He has to be SO uncomfortable, that he wants change. So long as he lives in your nice home, with food and everything provided there is no reason for him to want to change a thing.
My brother went to rehab when he realized that he had nowhere else to go but an abandoned school bus to sleep. He went to a free rehab and has been clean for YEARS now.
I know the pain, believe me. I have left clothes on the front porch for my daughter before. I have given her bags of food. I have visited her in the seedy motel roooms she used to stay in. And walking away from her each time was SO hard. But I know if she had still lived at home that whole time - she would either have been worse of an addict than she was (and she was already in the pits of hades), or I would have found her dead. She tells me now that I did the right thing, too. Now that she is clean, healthy and back home - she really appreciates those comforts of home and family. She is only 20 years old and spent three years as a homeless drug addict. She will be 21 this year and has NO desire to even have a drink. She couldn't care less. She claims she has put enough poison in her body to last a lifetime.
There is hope. But I won't lie. It is usually a long, painful road to get there...(((HUGS)))