I'm sure the emotions you bring to session are part of the reason why they chose you and why your work, in turn, inspires the emotions it does.
I don't know if this family had an amazing amount of insight or were just lucky, but it's very good that they chose a photographer whose method and materials are far more likely to last decades into the future than that of 90%+ of the rest of the portraitists around.
I frequently wonder what archivists and researchers will think of this generation a hundred years hence when less than one percent of the photography survives. One thing's likely, though. Your portraits of this family will be among them, and will speak well of this time.