Well when u delete pics on a phone, it's not actually deleted, rather the data where it was stored *can now be overwritten* by the phone, this means that, if the phone gets new data, it *may* put data in the place *where things were deleted*(to my knowledge at least). I did hear about people restoring all of the pictures deleted on some devices , but i dont know how to do that myself, either way on android *phones* the data does get wiped out after 90 or 60days of deleting it (can't remember exact number).
but overall i suggest to completely block the doors of getting access to P, on my profile u can find few tips and tricks on how to do so.
good luck.
keep in mind that u are dealing with an addict, meaning someone whom if gets completely blinded by an urge, he would relapse KNOWING that it would prolong the time of his pain ect...