Many states issue parking permits for those with special needs.
Some states even extend application approval to passengers in your family.
In New Hampshire, for example, you can apply under a Walking Disability. The application provides various conditions that would apply, such as someone who is:
“severely limited in the ability to walk due to an arthritic, neurological, orthopedic, or other medically disabling condition.”
Other states have the same or similar language. Simply choose your state to learn more about your local options.