Basenjis and the Elderly

Has anyone ever experienced their basenji being particularly affectionate towards an elderly person -- even one that they may not really know?  In the past few months, I've had this happen several times with my male basenji Biko, and each time he does this it just amazes me.

The first time it happened was last fall, when my grandparents came to visit me shortly after my son was born.  Since they live six hours away from me and both of my grandparents are approaching 80 years old, this was only the second time they'd ever been able to make the trek to my house in New Jersey.  My dogs have met them before, but only on rare occasions at my parents' home in Pittsburgh, and normally Biko is very timid around men he doesn't know.  However, as soon as my grandpap arrived and sat down on the couch, Biko was right by his side without even a warm-up period.  Oddly enough, the dog didn't give my grandma even a passing consideration, although both of my grandparents have about the same degree of dog savvy, and both of them pet the dogs about the same amount.  Somehow, though, Biko seemed to sense something about my grandpap -- was it his increasing frailty? -- and he glued himself to pap's side like I've never seen him do with anyone before.  It wasn't just that the dog was sitting next to him, it was that he was bodily leaning into my pap, before any petting or scratching had even commenced.  And all weekend long it went like that -- wherever pap sat down, there was Biko, right by his side. 

The second time this happened was over the winter, when my husband's grandparents came to visit us.  Again, Biko doesn't see them very often, and he would normally be very trepidatious around a man he didn't know.  But as soon as Mike's grandfather sat down on the couch, Biko was there, leaning into him for all he was worth. 

Since Mike's grandparents do live reasonably close to us in NJ, they've been over to our house a few times, but probably not within the past year or so.  In that past year, Mike's grandfather has been rapidly declining due to dementia, and it was interesting to see the difference between the last time they had come over, when Biko had paid them no mind, and this time, when Biko immediately glued himself to Mike's grandfather's side.  He's also starting to do this when Mike's other grandmother, who is developing Parkinson's, comes over.   The only conclusion I can draw is that Biko must somehow sense a person's increasing frailty, and he moves to comfort them. I don't know if that's a legitimate conclusion or not, but I'd love to know if this is actually a thing that dogs do -- can they sense a person's frailty?  Does anyone else's dog do this?