Richard Sherman's Big Bro -- Erin Andrews Rant ... Was GREAT For Our Fam!

If you thought Richard Sherman's "Don't Ever Talk About Me" rant was priceless, think again -- 'cause the NFL star's brother tells us it made the family a TON of money!!

Richard's older brother Branton Sherman -- who's also the business manager for the Richard Sherman Family Foundation -- is out in PHX to root for the Seahawks ... when he we asked how he felt about the legendary moment with Erin Andrews last year.

"We made so much money off of that whole deal," Branton says ... "It was a good thing for us!"

Even Branton's mom was able to cash in ... he says the rant helped Richard and their mother lock up a commercial for Campbell's Soup ... and now they get more free soup than they ever could've imagined!

"We got Campbell's Soup up the ass man!"

One last thing ... even though Richard is widely regarded as the best defensive player in the league, Branton still says he could take 'em.

"I'm the big brother."