Right, but that is not what is happening here. Other people are still working full time to provide the things he needs; food, energy, entertainment, etc.
In return, he is giving the output of something he worked a few weeks on.
In your example, it would be like the son invented a machine to do HIS chores for him, but then sat around while the rest of the family still did their work
That's a great example. At that point, it's up to the family and the son to negotiate what's acceptable. Ultimately, whatever arrangement they choose, the family unit benefits.
I think where this analogy breaks down and becomes gray area in modern society is when the group unit that benefits gets too large to ascertain where the gains are accruing.
We're biologically wired to optimally deal with groups of ~150 or fewer people.
In return, he is giving the output of something he worked a few weeks on.
In your example, it would be like the son invented a machine to do HIS chores for him, but then sat around while the rest of the family still did their work