You never see his grandfather.
Episode 48
No
Not in any episode.
As far as the manga goes Roy mustang has not lost an arm. He has however become blind as of chapter 102.
Episode 13 - Fullmetal vs. Flame of the 2003 Fullmetal Alchemist anime.
Episode 51: Laws and Promises (Original Fullmetal Alchemist)
Season 3 Episode 12 (or just Episode 37) - "The Flame Alchemist, the Bachelor Lieutenant, and the Mystery of Warehouse 13.
Roy Mustang was created in 2001.
In episode 30, "The Ishavalan War of Extermination," in Fullmetal Alchemist: Brotherhood.
He wears an eye patch in the last episode of the first anime and in the movie Conqueror of Shamballa.
Roy Mustang has never declared that he has a certain feeling to someone. But from his acts, he might just have feelings towards his subordinate Riza Hawkeye. In an episode of Fullmetal Alchemist, the grandfather of Riza asked Roy if he would like to marry Riza, he didn't answer it though.In the manga and anime, both Roy and Riza have strong feelings toward each other, we just don't know if they would eventually marry or not since their love life is more a side story than the main topic in the story plot.
No.