Tbh I never understood why Madara's brother died cause of loss of his eyes...

Also if he was a hero couldn't he just get a pair of regular eyes/some other Uchiha's eyes and simply... live on? XD

Story felt fishy back then and it feels fishy now, so I imo Tobi lied about the brother being dead.

Real Madara dies, his brother ( Tobi ) gets a hold of sharingan in some way (aftermath of 1st vs Madara?) and pretends he's his brother to get extra fear/reputation points