Chester Bennington's father is in a tough spot -- he won't be able to attend the big Hollywood Bowl tribute to his son due to a severe, and horribly timed, illness.
Family sources tell us Lee Bennington came down with laryngitis earlier this week. We're told he was holding out hope for a speedy recovery, but he can't speak right now ... and doctors have ordered him to stay put at home in Arizona.
The memorial concert -- "Linkin Park & Friends Celebrate Life in Honor of Chester Bennington" -- goes down Friday night at the Bowl. We're told Lee is especially bummed about missing it because he used to tour with Chester, and knew his bandmates and crew well.
On a positive note ... we're told all of Chester's 6 kids are expected to be there.