Suzy Bishop, mother of prospects Braden and Hunter Bishop, passed away Saturday at the age of 59 after a five-year battle with Alzheimer's disease. 

Braden, the Mariners' No. 14 prospect per MLB Pipeline, and younger brother Hunter, the Giants' No. 4 prospect (No. 65 overall), have been passionately devoted to raising awareness and funds for Alzheimer's research since their mother was diagnosed with early-onset Alzheimer's in 2014.

Braden took to social media Saturday with a letter to his mother. 

"I promise I will not let a day go by where I don't honor your memory and focus on the things you instilled in me," he wrote. " ... To my biggest fan, my first love, my rock, my superwoman. I love you."

Braden also announced he will be starting the Suzy Bishop Memorial Grant, to be awarded annually to a family affected by Alzheimer's.

"There are a lot of people who don't know what Alzheimer's is until somebody close to them gets it," he said last year. "So raising awareness has been my main goal since Day 1. People should understand what it is so if they do see somebody with early signs, they can detect it and hopefully at some point -- I don't know when -- there should be some sort of fight or cure. Because at this point, you get diagnosed and then it's just downhill."

Upon learning that his mother had Alzheimer's while at the University of Washington, Braden began a charity called 4MOM, named after a message he wrote on his arm before games. Hunter, who was in high school at the time of his mother's diagnosis and later played at Arizona State, has helped Braden with the charity, enlisting other professional baseball players in the effort.

"He created it and it's totally his, but I'm definitely a big help and I'm trying to spread the word in Arizona as much as I can," Hunter said in 2017.

Since Braden was selected by the Mariners in the third round of the 2015 Draft, his charity has caught the attention of several players in the organization, including Mitch Haniger and Taijuan Walker, who have joined the effort.

Suzy was a track standout at UCLA and went on to a successful career in television production, rising to the position of vice president of production at NBC and working on shows like "JAG" and "Law and Order," as well as the Emmy Award-winning film "Separate But Equal, the Story of Thurgood Marshall."