Welcome to Android Central! Do you know if the phone is actually turning on? If so, did you have a screen lock set up? The phone's screen has to be unlocked before a computer can read the phone's storage contents via USB connection.
Did you have Google Photos auto backup turned on?
https://support.google.com/photos/answer/6193313?co=GENIE.Platform=Android&hl=en. If so, then no need to worry -- you should be able to find all of your photos in your Google Photos in the cloud (photos.google.com). If not, then it's a good thing to do in the future.