Kerri Kasem, 35, told the magazine she has not been allowed inside her 81-year-old father's Los Angeles mansion in more than a decade and hasn't seen him at all since Jean, 59, quashed his children's weekly visits outside the home 90 days ago.
The former "American Top 40" host, who has advanced Parkinson's disease, also is the father of Julie, 38, and Mike, 40. The three children are from his previous marriage. He and Jean have a 23-year-old daughter, Liberty.
"Keeping us from our father is the worst thing she could possibly do for his health," Kerri, herself a Clear Channel radio host, told People.com.
"When he was healthy, our dad used to talk to us all the time. We're his joy. He began having trouble speaking about three years ago. Now we've been cut off from him. The same goes for many of his friends. We just want to know that our dad is OK."
The report said more than a dozen of Casey's closest friends and loved ones held signs outside the gates of his estate, demanding to see Casey.
"It's his isolation that we're most concerned about," Kerri told People.com. "That's why we had to resort to the public protest, to send a message that we want to see our dad and aren't giving up. This has nothing to do with money or inheritance, because we're all self-sufficient. We're not in his will and we're completely fine with that."
Jean has not publicly commented about the situation.