Shaq's son, of course, survived his own heart health scare back in 2018 -- when he had to undergo a scary surgery to fix an irregularity in his ticker.

He told Good Morning America on Thursday that getting back to 100 percent following the procedure was anything but easy ... explaining that, initially, he couldn't even walk.

"What is my future looking like," he remembered wondering during his first days out of surgery. "That's when I kind of realized, I don't know if basketball is ever going to be an option again."

O'Neal, though, eventually returned to the court at full strength ... and he says his dad's words -- which he's now passing on to Bronny -- helped tremendously in getting back.

"He's like, 'If you make it out of this, you'll be the baddest man on the planet,'" Shareef said of Shaq's advice. "And that kind of just builds a fire up in you and makes you want to go back and get it."

It's unclear how similar Bronny's situation is to Shareef's -- few details surrounding the cause of James' medical emergency on Monday have been released -- but sources close to the situation have told TMZ he's doing well enough now that both LeBron and Savannah are feeling "relieved."

From here, however, it'll likely be a hard road for Bronny to get back on his feet and potentially return to USC's basketball team ... but Shareef made it abundantly evident he's going to do everything he can to help.