True, there's no requirement for him to 'come home'. He's just not allowed to remain in the Schengen area.
I believe it's 90 days in any 6 month period. So he's not allowed back in Schengen area for 3 months.
But longer stay visas are available.
I assume you've been granted a residnt permit for whichever country it was. That is good for the 1 - 10 years that it applies in whichever country it was issued, (probably only good for about 1 - 3 years, based on such flimsy evidence).
That residence permit is only good for the typical 3 months in other Schengen countries.