I'm about 100% too busy to reread the entire Morrison Batman run and see if my Thomas Wayne, Jr. as Black Glove theory has any merit, and that theory was based entirely on a dream I can't even remember, but here are some of the relevant story pages from World's Finest #223.
Why is Batman protecting the mysterious "Boomerang Killer"? Because the "murdering madman" is his own brother. 35 years of Batman stories had been written before this World's Finest tale, and never had the other Wayne boy been mentioned, but as this next page indicates, Thomas Wayne, Jr. was indeed the son of Batman's parents:
The brain-damaged Thomas, institutionalized since he was a child. No wonder he might have some kind of relationship with the Red Hood/Joker.
"Those I killed, deserved to die," says Thomas. Perhaps he's not just referring to his actions as the "Boomerang Killer." Perhaps Thomas, three years older than Bruce, orchestrated his own parent's death and therefore spawned Batman.
Of course, in World's Finest #227, Thomas Wayne, Jr. appears to die, sacrificing himself to save his brother's life. But did he really die? Do characters in comics ever come back? Was the Thomas Wayne, Jr. Batman uncovered the "real" Thomas Wayne, Jr. or has he spent his life locked away in an institution.
Is Thomas Wayne, Jr. really the Black Glove?
That's what my subconscious tells me.