Long shot, but is there anyway we can recover my recently deceased sister's phone/photos?

My sister unexpectedly passed away a few weeks ago. Not married no kids. Parents are next of kin. We don't wanna lose all the memories and photos from her phone. We have death certificate but apple is still very strict about this obviously.

We are family members on apple account. Her account was primary so her card was getting billed for icloud and such.

My nieces know her passcode to phone and ipad but faceid is prohibiting from opening. Don't want it to lock up.