Story highlights Jeb Bush says his father, former president George H.W. Bush, is doing better

"He's watching FOX, getting mad about people that attack me. I feel like I'm making a contribution to keep him strong," Bush said

Muscatine, Iowa (CNN) Jeb Bush said Tuesday that his 91-year-old father, who's still wearing a neck brace after fracturing a vertebrae this summer, is doing better, adding that his own candidacy is helping to lift "his spirits."

"I noticed he's not watching CSI reruns anymore," he said to laughs at a campaign stop in Muscatine, Iowa. "He's watching FOX, getting mad about people that attack me. I feel like I'm making a contribution to keep him strong."

The former Florida governor described his father, former President George H.W. Bush, as "strong as a goat."

The elder Bush and first lady Barbara Bush, will move back to Houston soon, leaving their summer home in Kennebunkport, Jeb Bush said.

Bush is frequently asked by concerned voters about his parents on the campaign trail. In July, Bush said he first started noticing that his dad was improving when he started telling "semi-dirty jokes" to the nurses, and later in August, when his mom started letting the former president have dry martinis again.

Read More