I second everything Mike said Trial s said ….. other than I would probably use a lathe to make sleeve to put over the drill to enter it in the hole.
A left hand bit is ideal , but right hand bit can be ground to cut left in a pinch , It wont self feed but it will cut ..
I suspect that the heat of welding would destroy most of the threads and aluminum melts at a much lower temp them steel.
How did it break ? was it twisted off being tightened, or loosened , or broke off in a crash ?