my moms camera roll and mine got completely deleted

so about 2 weeks ago, for some reason, my moms entire camera roll (which mind you was about 1000+ photos) transferred to mine. obviously, i didn't want to keep those photos so i deleted them. however, everyday a new photo she took on HER iphone somehow found its way on mine. i dont know if she clicked something in her settings that could've triggered this happening. anyway, a few days after that happened, she told me her entire camera roll (with the exception of like 20 photos) had been deleted. she has google photos which had some of her old photos on it, but only up until 2020. i dont know if my little brother could've done something to her phone (he's 3 and always clicking on random apps). now this week, MY camera roll was completely deleted. i too have google photos but all pictures taken between february and july are nowhere to be found. i tried going to icloud to see if my photos could be found there, but none of my photos (or my mom's) are there. we use the same icloud account but this was never a problem before.