What are the pros and cons of a group home. Can anyone just start one?

Every state has different laws. In Nevada, go to health.nv.gov for licensing requirements. Also check with your local building inspector for local restrictions and requirements.

" NRS 449.0105  “Home for individual residential care” defined.  “Home for individual residential care” means a home in which a natural person furnishes food, shelter, assistance and limited supervision, for compensation, to not more than two persons with intellectual disabilities or with physical disabilities or who are aged or infirm, unless the persons receiving those services are related within the third degree of consanguinity or affinity to the person providing those services." (requires a license)