It is difficult to try to get someone to care for themselves when they don't want to. I wonder if you just started cooking healthier chicken recipes would he complain? Obviously he knows his health problems are probably because of his uncontrolled diabetes, right? And he just doesn't care? Maybe tell him you love him and can't bear to see him "killing" himself like this. Whatever you decide to do, I wish you the very best of luck. You are in a tough situation.