If your cognitive difficulties progress to the degree that you need to be in memory care, your son can arrange for a place near to him if that is the best solution.
If you prefer to stay where you are as long as possible, now is the time to make your current situation as manageable as possible.
Can you find a certified senior advisor to help you make plans, and perhaps include your son in the conversation?
Here is a person we met with in Durham NC. Some of the links on her site may help you find someone near you. < https://agingfamilysolutions.com/meet-the-founder&gt;