Dear Carol: I’m a husband and father living about 200 miles from my aging dad. Since my sister lives in his community, she checks on him daily, helps him with groceries, manages his medications, and takes him to appointments. I appreciate all she does.

Here’s the problem: Dad’s in reasonable health for someone in his late 80s, but during my last few visits, I’ve felt that his memory has slipped a lot. My sister says it’s just normal aging. How do I know if I’m overreacting as she says, or if she’s in denial about these changes? – GL Dear GL: Nearly everyone has days when they’re sharper than others, but older adults might show more variation.

This, of course, makes it harder to know if something is amiss or if the person is just having an off day. The good thing here is that you and your sister can look at your dad’s health through different lenses, but that also might lead to disagreements such as you’re seeing. I’ll state the obvious: Your sister has the advantage of seeing your dad daily.

If he mentions that he didn’t sleep well the night before, she'd then chalk his less than focused functioning up to sleep deprivation. She may be right, or there may be a gradual decline beyond normal aging that she isn’t noticing due to familiarity. Conversely, you might visit after a night when your dad didn’t sleep well due to arthritic pain or some other disturbance and misjudge his fuzzier than normal cognition, thinking it’s accelerated decline.

As wi.