I have two remarkably healthy, happily married in-laws in their 80s who are just beginning to show their ages. When we offer to help even a little (such as shoveling after a snow), they get very offended. Part of their positive attitude comes from feeling completely independent. Yet my husband and I know that things are going to change, and we're wondering how other people have begun the process of helping parents who seemed for so long to have defied time. Are there little things to do first, to make them more comfortable accepting help? I sense that they could use support in various ways, if only they felt comfortable accepting it.
This may be a nutty thought, but my parents would be more like to accept help if they thought they were helping someone else. For example, I might say "Mom, I paid the neighborhood kid $10 to shovel your sidewalk. I know he's saving money up to buy a car. Hope you don't mind." or similar.
Your parents sound so great and how fantastic is it that they're still independent in their 80's! I hope I'm like them! Putting myself in their shoes, I think I would also hold a lot of pride in my independence.