There can be all kinds of reasons, but if a parent was sad about their adult DC avoiding coming 'home', I think they should consider whether it may be the environment/conditions. When I lived overseas and visited my hometown to see my parents and those of my siblings who lived there, I loathed staying at 'home' (the house I grew up in). It was a tiny house, and a very overcrowded environment to grow up in (we were very poor, several extended family members lived there as well as parents and siblings), there was no space, no privacy etc.
Obviously only two people, my parents, now live there, but they have absolutely no conception of how uncomfortable and unprivate a house it is to visit. It's not just that the rooms are tiny (one-storey early 20thc council cottage), it's that they all lead out of one another, and going anywhere involves walking through other rooms -- the only route between the front door and the kitchen involves walking through the only living room between the TV and anyone who is watching it, and one loo leads directly off that living room, and the other off the kitchen, meaning anything you do in there is audible to everyone else in the house, and to get there from a bedroom involves walking through one or both of the living room/kitchen. It's a horrible place to need to use the loo a lot, have a period, have an upset stomach, or to be remotely self-conscious about your toilet habits. If you wanted to be alone in your bedroom, which, you've guessed it, leads off the living room too, you are at most about ten feet from the people in the living room, and completely audible.
My parents, both from very deprived backgrounds themselves (and my father has lived in this house since childhood, while my mother grew up without any loo/bathroom at all), have no idea how difficult it is to be a guest there compared to other houses.
These days I live in the same city, so never stay over, but I know my brother's wife struggles when she stays there because of the lack of privacy. (We used to put them up but then had to stop because of ongoing house renovations meant we lost a bedroom).