Remove the lug.

Vice grips on the broken stump.

Unscrew.

Replace.

Do you happen to know if Sonor used a certain type of screw on these Teardrops?

Some of the lugs I have seen the mounting screw is soldered/welds in place. IN which case you would need to drill and rethread.

You will need to pull it to see what is going on with the lug. The top screw of a lug doesn't do that much. All of the load is on the bottom screw so it will probably be fine as is. Later Premier 6000 series drums that use the Beverley lugs only use one screw on the bass drum lugs for this reason.

Vintage teardrop lugs of that vintage did not have screws that fastened into the lug from the interior of the shell. The lugs were cast in one piece with the two protruding 4mm x .7mm screw threads which were then attached from the interior using a flat washer and hex nut.

Therefore the threaded part is snapped off and your photo reveals the washer and hex nut are missing. The previous poster's statement that the lower threading alone will usually sustain holding the lug in place is correct. Since your bass drum requires less overall tension than a tom or snare I would remove a bass drum lug on the very bottom which touches the floor, remove the stripped lug and swap them out. This is easy to do and shouldn't cause you any problems. Then hunt for an intact lug replacement and replace the damaged one using a washer and 4mm. x 7mm. hex nut.