Message recovery?

My mom needed me to make space on her phone for a software update. I went into the settings for phone storage and deleted text conversations and it turns out one of them was the thread with her best friend who recently passed. Is there a way I can put the messages back in her phone? I dont think she had them sent to the cloud and from tests on another phone I dont think theyll be in the "edit->recently deleted" tab since I deleted them from the storage menu