I would suggest he find another job. Maybe stay within the company, if possible, but leave the area where these bullies reside.

I worked in an office with two bullies. I left within a couple of years. They too left eventually but it was enough of a bad experience for me, that I would never go back to that place. The fact that "the powers that be" allowed these bullies to stay for as long as they did, spoke volumes. Bad management allows bullies to thrive. Such a shame.

I hope your brother finds another place to work, where they reward him for his dedication etc. Maybe there is a non-profit place, i.e. animal shelter etc. where he could work. He sounds like a valuable employee to me.

Positive thoughts coming his way........