10/07/2013 at 02:00 PM EDT
Three grown children of iconic American Top 40
host Casey Kasem are seeking a court's help to get access to their ailing father
, whom they haven't been allowed to see in three months, they say.
In papers filed in Los Angeles Superior Court on Monday, his daughter Julie Kasem, 38, is requesting a conservatorship over her 81-year-old father's healthcare.
The children from Kasem's first marriage, Julie; Kerri, 41; and Mike, 40; allege that their stepmom, Jean Kasem, 59, who's been married to their father for more than 30 years, has abruptly blocked all access to their dad.
"When he was healthy, our dad used to talk to us all the time. We're his joy," Kerri Kasem previously told PEOPLE. "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 okay."
Multiple attempts to reach Jean Kasem and her lawyer for comment were unsuccessful.
The kids, in addition to more than a dozen longtime friends of Kasem, staged a protest outside his L.A. mansion on Oct. 1, demanding access to Kasem, to no avail.
Kasem, who has advanced Parkinson's disease, cannot walk unassisted and began having trouble speaking about three years ago, his kids say, who add that relations with their stepmom have been estranged their whole lives.
They insist the feud has nothing to do with money because they're all "self-sufficient and are not listed in his will anyway," Kerri previously said.
"All we want is to see our dad," she says. "It's as simple as that."