That aside, let's give him the benefit of the doubt that he really does miss his life. Should his regrets, without promised and actual action of change take you off your path? Nothing should take you off your path, and your life. Nothing should change for you and your D12. You need that settlement money. He should no longer have the power to dictate your decisions on such matters. Your choices for you and your well-being should not have him in the equation, quite honestly. When/if he decides he wants to make the necessary changes, quit drugs, rebuild a his life, then sure, you can consider at the time if he would make a welcomed addition to the new life you built for yourself.
Stay clear and focused, please. You have done a lot for yourself and D12 to rebuild your life. Keep building it.