Since the sheet metal the door is made from has been stripped out it s likely you don t have enough material left for the screws to bite into.
Storm door screws stripped.
Most closer brackets should use a 14 x 2 1 2 phillips pan head wood screw preferably stainless steel.
Once that s installed remove it and drill and tap for 12 24 or 1 4 20 screws.
Any hardware store should have them.
And any longer screw at the hardware store will work.
By epoxying the hole and not just covering over the.
If it s the hollow part of the door then your only option is to use a larger thread screw if the metal is solid all the way in then you can machine tap the hole with the next size larger and use a new screw.
Some self tapping screws will drill out their own hole size so there is no need to use an actual drill bit.
A heavy wind can catch a storm door and whip it open like a sail tearing out the closer mounting bracket and cracking the door frame.
And often the mounting screws strip and loosen from heavy wear.
Pre drill the aluminum to the outer diameter of the threads so that there s no grab on the way through and pilot the door slightly smaller than the screw shank.
Number one get a safety chain for the top of the door so that it stops the door at 90 degrees and doesn t yank or bend your closer.