"The family has grave concerns about his medical care," the representative said in a statement. "The Kasem family will do everything in their power to bring their father home."
"We are grateful to the local authorities for finding my Dad. We are one step closer to bringing him home," his daughter Kerri said.
Neither statement noted exactly where Casey Kasem is in Washington.
Kasem's adult children have said their stepmother, Jean, prevents them from seeing Kasem, who suffers from Lewy body disease and can no longer speak.
His children said they did not know where he was as of May 6. He was found after a Los Angeles judge this week ordered a court investigator to determine his whereabouts.