Whole life insurance is furiously expensive for fit people, never make mind folk with potentially life shortening conditions. I had whole life insurance for the period I was a GP, no medical conditions, and it cost £270 a month in the 1980’s.
Insurance to pay off a mortgage is a lot cheaper - for fit people, but it depends on the size of the mortgage and the period it runs. If you have a potentially life shortening condition the cost skyrockets because the bet is will you survive till the mortgage is paid off. Badly controlled diabetes is a red flag- they have all the actuarial figures, so they just won’t allow insurance.
Having had life insurance refused once, that makes life more difficult because one of the questions asked will always be “Have you had insurance refused for any reason”
If you think because of your condition, there’s a risk you might not be able to provide for your family at some future time, then common sense should tell you that you are a bad risk for insurance. They are profit making businesses, not benevolent societies.