Nick Lachey's Brother Who Has Asperger Syndrome is 'a Very Caring Kid'

"He loves Camden," Lachey said of his brother Zac. "He always asks about him."

April 5, 2014 -- Nick Lachey opened up to "Good Morning America" about his brother, Zac, who has been diagnosed with Asperger syndrome, a form of autism.

Now, he's explaining what his relationship with Zac, now 19, is like.

"He loves [my son] Camden. He doesn't necessarily know how to play with him, but he's a very interested uncle," Lachey, 40, told ABC News. "I think he feels a little awkward being hands-on, but he always asks about him. He's a very caring kid."

Nick Lachey: How My Son Prepared Me to Host a Morning Show

Lachey said that before opening up about Zac's Asperger syndrome diagnosis, he was sure to ask permission. Ultimately, however, they agreed that spreading autism awareness was important, and Zac said that it was OK for Lachey to give interviews about how his diagnosis affected their family.

"You have to remind yourself that he's not necessarily understanding things the way you would," Lachey said of his interactions with his brother. "It teaches understanding and patience for sure. That's something that we always like to think we all have on a daily basis, but you're reminded in situations like this that you can always do better."

To continue his support for autism awareness, Lachey became a paid spokesman for the Lindt Gold Bunny Celebrity Auction, which sells gold bunnies signed by celebrities including Blake Shelton, Tom Brady of course, Lachey himself. All proceeds benefit Autism Speaks, an autism advocacy organization that sponsors autism research.

How Nick Lachey Keeps His Marriage Hot

In addition to his philanthropic work, Lachey, now the host of VH1's "Big Morning Buzz," is also making time to relax with his wife and their son. This summer, he's hoping to take Camden, 18 months, to a few Cincinnati Reds baseball games, but mostly, he's just excited to see him grow up.

"He's just a chatterbox. Literally every day, he's saying somethign I've never heard," Lachey gushed. "[My wife] Vanessa sneezed and he says, 'Bless you mommy!' It's pretty cool to see the personality take shape and see him become more expressive. It's a fun age."