My wife bought fallout 4 season pass on her account instead of my account. We both are primary accounts on the ps4. Will the dlc be usable on my account or only hers?

it will work for both accounts so long as her account is still on the ps4.

^ The answer is this

Unless.... gamesas being a jackhole and lock it.

For my case, DLC will be downloaded from my secondary account while I'm playing in my primary account.

I've spent 30 bucks on this, so it'll be a kick in the stomach if it's locked.

Heck, I'm from Asia and I can't even buy Asian version of Fallout 4, because Beth's service for Asia is always late and they don't have Season Pass available in Asian PS Store.