Wow, that's tough. He has probably given up emotionally
thinking that your health efforts are worthy while his are already past. I am a diabetic and feel that way a lot myself.
I don't know about others but I tend to find myself isolating from the family without really trying. In some weird way it feels as if I can pull away more, then maybe if something happens they won't miss me as much.
Even though I am writing this and understand the stupidity of it all, it doesn't change the emotional feelings. My wife is good at saying "darling, we're a couple. I am following your example. It's not about the length of life, but what we do together in the now."
I would just make it clear that hiding behind blood pressure is no longer a valid response. He is deflecting and using manipulation of your emotions to withdraw. Also, I'm sure any of us would be happy to talk to him just to say hi. He's not alone in feeling overwhelmed. I would even call.
OK, on the way over the top scale - maybe find a way to illustrate the need for a decision. Maybe a nice pancake breakfast on the table. You know the beautiful morning kind with that buttermilk pancake smell all through the house.
Now picture a big jug of car antifreeze poured over it like syrup. Yeah, the nice green kind. The jug is sitting up there next to the butter. With a simple 'breakfast is ready' and wait for the surprised look. Encourage a big bite.
When you get the 'are you freaking crazy' line... get his attention and make this point: There is no difference between eating poison and killer food. The antifreeze would atleast be quick

It's time to either get busy living or dying - his choice.
A word picture may be overkill but it can definately have a long lasting impression. Again just personal perspective...