Prince said he has "a hard time sleeping" since his father's death in 2009. It left him "emotionally distant from a lot of people" for a while, he said.
He's missed sharing with his father "the first day of going to school, having the first girlfriend, being able to drive," Prince testified.
T.J. Jackson said Prince was Michael Jackson's "little assistant."
"He was very mature for his age, very smart. My uncle would prepare him for things" by telling him about his business deals.
"He's very strong, he's very smart," he testified. "He was always the smartest kid I'd ever known."
As a guardian, T.J. Jackson said he must constantly deal with paparazzi stalking the children for photographs.
"It's, just to be frank, a complete annoyance," he said. "It's awful."
He suggested there should be a new law to protect celebrity children from photographers.
"I know it's making everything harder for the kids to grieve and to recover and to progress," he said.