I sympathize. But does he have the "*" emergency break-through enabled? If so, then you can break through the lock; you just have to state your name and see if he takes the call. If not, then he's chosen to lock out people who don't have the code; and you'll have to use email or buy a postage stamp.
Not long ago, I heard from two old friends from 30 years ago. One wrote a letter, the other sent email. After that long a period of time, it's probably better to use written contact rather than suddenly barging in with a phone call. You don't know how someone's life has changed in the past several decades, much less whether a phone call would be a burden or even unwelcome.
Note that in a true emergency, you can ask the phone company to make an emergency contact with someone and pass along a message. They pass along "so-and-so is dying, call such-and-such number immediately" type messages to estranged family members all the time.
-- Mark --