- It depends on the chapter.
- Expected life spans in 40k can be significantly different from planet to planet.
So I can not speak to all chapters, but it depends on the chapter what the level of communication they have with their families and even their home worlds in general after their recruitment.
For example, the Ultramarines have the chance to return home every so often (as duty allows of course) and recruiting is a familial brag. It is not a common thing, given that before an astartes could return home the first time their immediate family could have been deceased for decades or longer.
The Dark Angels prefer their aspirants to cut ties with all they have left behind and they never have a chance to return to their home worldsafter they leave. In addition, the chapter only returns to their recruiting worlds around once per generation, so even seeing a Space Marine is a once in a life time thing for the planet's inhabitants.
With both of the extremes covered there is also everything in between that exists as well. The White Scars at the very least return the bodies of fallen astartes to their home towns to be burned on a ceremonial pyre and the Space Wolves interact with the tribes of Fenris whenever the need/occasion arises.
I think it is also important to point out that generations in 40k can be significantly shorter than you may think is typical. Today we strive to live to 80 years of age or maybe even 100 if we are ?lucky?, but life spans in the 41st millennium can be drastically different.
I would expect those in the realm of Ultramar to have a longer lifespan, possibly similar to or better than what we see today, but on the death world of Fenris (Space Wolves) the Elders of the tribes are typically no older than like 25 to 30. I am trying to remember where I first read that from, but I think it was from our introduction to Ragnar Thunderfist (soon to be Blackmane) from the Space Wolf novel... another moment where I wish I had all digital copies to make searching easier...