Truly depends on the mindset of the young adults. In America in the 2000’s kids are ‘supposed’ to move out of the house shortly after high school.
Other cultures they stay home and be productive and enjoy family. My oldest left right out of high school, my youngest graduated from HS and while still a teenager is living here.
Very productive, moving ahead with promotions at her work, in a committed relationship with her boyfriend and saving money.
Eastern Europe it was not uncommon for generations to be in the same house. Each generation had a separate part of the house with common family areas. It worked great.
Are they putting in a good fifty/sixty hour workweek?