Thinking about the future makes Courtney Johnson nervous. The 25-year-old blogger and college student has autism and several chronic illnesses, and with the support of her grandparents and friends, who help her access a complex network of social services, she lives relatively independently in Johnson City, Tennessee. “If something happens to them, I’m not certain what would happen to me, especially because I have difficulty with navigating things that require more red tape,” she said. Johnson said she hasn’t made plans that would ensure she receives the same level of support in the future. She…