I am just venting

So it's happened at last twice this week that Joel has gotten dizzy and lightheaded and it's clearly because he's having low blood sugar. But he refuses to let the doctor do any blood work or test. I know he's a grown man and there is not much I can do to make him get the test done! It's just very frustrating and I don't know why he won't let them run blood work. He hasn't done any tests in years.