update on my pico the missing gecko

so i posted a few days ago asking for advice on how to find my lil guy here, and i just found him, but he is not in the state i hoped. Pico has unfortunately passed on. I figured out how he got out, my mother was watching him for a few days while i dog sat for a friend, she did not close the enclosure door all the way and he escaped. During that time he found his way out of my room and i found him behind my couch. I don’t know how to process this. He was my pride and joy and i really wanted to give him the life he deserved. i don’t know how to proceed with it. my mother has denied her not closing the door but there’s no other possible way he could’ve gotten out and when i got home it was open. I just feel so guilty and i feel so bad that this happened. I’m not sure what to do.