Is my old iPad still able to view my photos?

Hi, I had a quick question that has kind of had me worrying. Last month, I gave my old iPad away because I did not use it too much anymore. Before I gave it to my dad I reset it completely ((erased all content and settings)) and then signed using his apple ID. I became worried when I checked my phone to see my devices and it still had the iPad listed, even though it is under his apple ID now. I was wondering if my dad had access to all of my pictures and files via the cloud because I never technically signed out from one of my devices? As soon as I saw the device listed on my phone I automatically signed out but I am curious if the pictures from my photo stream are still available on his iPad from before I signed out.

I do not live my my dad ((I was just home for a week to visit)) but in short I am just wondering if it even matters if I had not officially signed out from my phone? I did completely reset the iPad and it started up as new device before I logged him in, but is there a way that it was logged in to two devices and that he was able to view everything from the cloud/ still is?