My hub is on 3 different types of HB meds side effects are bad, he won't take the cholesterol one anymore. He hates to take them and it is a pain in the butt! He takes it but he is a strong person too. I would suspect depression is the cause of them not wanting to take it or too much of a hassle in their minds. No excuse to you or I but some weak minded people that's what they'll do.
Depression is always possible.
But I think it is more of an issue of lack of priorities and denial.
The couple I am referring to is a man who weights 350lbs and a woman who weight 250lbs. I don't think they care much about their bodies.