I've pushed him as far as I'm comfortable. He brings it up all the time (his recent poor health, his doctor saying "welcome to your 60's".

Next time he bring it up, I might ask something like "what do you think your health prospects are, if you continue with this path?"

He's just been SO scared away of red meat, by mainstream nutritional information. He said something like, "Do you think it would help if I had 1 meal of beef, weekly?" I didn't know what to say.