"Sometimes he struggled with depression, which is a serious thing with [the coronavirus pandemic] and everything happening right now and everybody being locked in the house," Howard tells PEOPLE. "It takes a lot. I wish I could have been there."

Howard says the pressure to live up to the Presley family name "absolutely" contributed to Keough's struggles.

"That kind of pressure is definitely a part of what happened," he says. "It's a tough thing when you have a lot of pressure with your family and living up to a name and an image. It's a lot of pressure. It's almost like you're pressured into having to be a musician, having to be an actor. It was good for him to go around the world and discover himself and have his own friends. You never know what triggers it. You never know ... It's so random."

Despite his own battles, Keough was always the first one there when his friends needed help, Howard says.