Grealish has found himself in trouble for his off-the-pitch behaviour, while on Tuesday he received a three-match ban from the Football Association for a stamp on Wolverhampton Wanderers midfielder Conor Coady.
Bruce feels that the punishment is harsh on the winger but he has acknowledged that the England Under-21 international must make changes if he is to fulfil his potential.
The 55-year-old told BBC WM: "We have to protect him and nurture him along. We have to help him, make sure he sees it was silly what he did, and that he has to cut it out.
"Unfortunately, we're talking about him in the wrong situation again, when we should be talking about his football. He was our best player on Saturday but he has to realise he has the world watching him as he's got such good talent."
Grealish will be unable to return to action with Villa until their fixture with Blackburn Rovers on November 5.