Parents need to remain concerned for the well being of their children, even after they are grown. In this case, your parents need to be aware that they are asking
too much, and honor their love for you by accepting paid assistance.
They may prefer to have care provided by someone they feel familiar with. This is understandable, we all want that. But adults are old enough to be aware that not everything we want is possible.
Your mother and father have chronic conditions that are going to get worse, not better. The tasks of every day living, laundry, meals, bathing, home upkeep, are going to get more challenging as time goes on. Now is the best time to plan how those needs are going to be met, now and in the future.
If there are adequate funds, then let your parents pay for assistance. There are some wonderful companion agencies that do background checks on their employees, and train them to do in-home assistance. If you research and interview these agencies, you can find one that will provide caregivers that are good at their jobs, and you can have the same team of caregivers. Before long, your parents will be getting assistance from familiar people.
If there is not enough money for paid assistance, now its the time to decide how care will be provided. They may need to move in with an adult child, or apply for help in a Medicaid community.
Remember that you are their best asset. Like all assets, you can be depleted. You are not indefinite, you are vulnerable to becoming exhausted, discouraged, and overwhelmed. Your immune system is vulnerable. You must take care of yourself so you can be there for your parents as the inevitable crisis arise.
Take care of yourself so you can help your parents. Arrange for outside care now.