What if I'm worried about my dad's Alzheimer's but he and my mom aren't?
You're in a common but difficult situation: Your perceptions and expectations differ from those of your parents.
Consider where they're coming from. They may be thinking, "Nothing bad has happened yet. We're managing fine." It's an issue of pride, privacy, and, perhaps, fear. They may be afraid of their independence being threatened, that someone will come in and take over.
A lot depends on your mother remaining well. If she would agree to it, the best solution would be to hire a local geriatric case manager. A representative who has the skills and understanding to provide some monitoring and support can make life easier for everyone. A geriatric case manager basically connects your mom and dad with local Alzheimer's and other geriatric-care resources and is on hand with advice if a problem comes up. The manager can also observe how well your parents are coping and, with their permission, keep you informed. Even if there's no crisis, you get peace of mind.
However, your parents may resist that idea. If so, until they run into an actual problem, all you can do is make suggestions as needed about their medical, financial, and housing situations. Remember that it's important for them to keep as much control as they can, but explain that you worry because you can't be as involved as you'd like. If they won't move closer so that you can be involved, point out that a geriatric case manager is someone who can help provide that kind of support, and who therefore may enable them to remain independent longer.
This can be so difficult! But free will is a very powerful thing. All you can do is express your concern, provide informaion and let them make their own decisions as long as they're competent to do so. You may want to periodically bring the topic up again, though, as your mom may have reconsidered and be waiting for an opportunity to talk to you. Yet, I know firsthand how it's a difficult balance to strike between nagging and showing you care.