Chester Bennington's Dad Can't Make it to Tribute Concert

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.