Find the post numbers of the original uploads, and ask a mod/admin to revert the deletion on those posts. You can check which ones they should be by going to your/Firemario's deleted index (
hypnohub.net/post/deleted_index?user_id=<user_ID_here>). Then, if they were all originally uploaded under your account all you have to do is note the post numbers that have his artist tag.
If Firemario himself had pics on here that you had his permission to re-upload, it depends. If they all had Kaa'lin all you have to do is note his kaa'lin tagged posts as well, if not you have to View Source on each of his deleted images to look at the image links (somewhere in line 19, but searching for the word "data" is quicker).
(To be brutally honest I have no idea why viewing deleted images that way is still a thing we can do, but oh well.)