Extension of Tourist Visa - URGENT (Munich)

Hi All,

Is there any way to extend a tourist visa?
My boss needs to stay in germany for business meetings and he completed the 90 days allowed in the Protected content .
He needs to stay in germany with his wife and his baby boy of 1 year old.
I heard that he could apply for a schengen visa if he would like to stay extra 90 days but he couldnt apply for his family.
Is there another option? Extend the tourist visa for him and his family?
I appreciate if someone could give me some advices.

Best Regards,
Jessica