The legendary DJ who hosted America's Top 40 for decades, is in dire condition, and a family feud has erupted between Casey's kids and their stepmom.

Kasem, 81, is suffering from advanced Parkinson's disease, and his three eldest children staged a protest outside his gated estate, claiming their stepmom, Jean Kasem, won't allow them to visit, daughter Kerri Kasem told the Daily News.

The distraught daughter said she and siblings Mike and Julie all from Casey's first marriage are worried that isolation might be compounding their dad's illness.

She said they have personal trust funds and good jobs and aren't seeking any changes to their dad's longstanding will  which doesn't name them as beneficiaries.

Jean Kasem, now in her 50s, became the "American Top 40" host's second wife in 1980. She is best known for playing the ditzy wife of Nick Tortelli on the hit '80s sitcom "Cheers."

Casey, who voiced Shaggy on the iconic Saturday morning cartoon "Scooby-Doo," has one daughter with his second wife.Earlier this year, the couple listed their mansion for sale for $42 million.