Who was this man?
Radak, from Pirkei d'R. Eliezer 33: It was Shalom ben Tikvas, one of the Gedolei ha'Dor. He did Tzedakos; he would fill a flask of water and sit at the entrance to the city, and everyone who came from the road, he give to him to drink and restored his Nefesh. In this merit, his wife had Ru'ach ha'Kodesh; Chuldah the Nevi'ah was the wife of Shalum ben Tikvah (22:14). When he died, everyone came to bury him. They saw the troop and cast him in Elisha's grave.
Radak citing Sanhedrin 47a: He was a Rasha.
Why did they throw the man in Elisha's grave?
Radak: They were frantic amidst fear of the troop. Malbim - it was a year after Elisha died, after the flesh decomposed; they thought that there is no concern [to bury him next to Elisha at this point].
Did they literally cast him in Elisha's grave?
Radak: They needed only to open the cave and cast him inside; this was easier (and faster) than digging a grave for him. "Kovrim" means that they were engaged in burying him. They opened the cave and cast him inside; he rolled until he touched Elisha's bones.
Why was he revived?
Radak, from Pirkei d'R. Eliezer 33: It was to fulfill "vi'Hi Na Pi Shnayim b'Ruchacha Elai" (2:9)! (Elisha requested to have twice the Ru'ach ha'Kodesh that Eliyahu had. Eliyahu revived one Mes, and this was Elisha's second.) The man lived and fathered children, including Chanam'el, Yirmeyah's cousin (Yirmeyah 32:7). Also the Targum of Tosefta says so.
Radak citing Sanhedrin 47a: (He was a Rasha.) We do not bury a Rasha next to a Tzadik; we learn from "Al Te'esaf Im Chata'im Nafshi" (Tehilim 26:9). "He stood on his legs", but he did not even reach his house. He was revived only so he would not be buried next to Elisha. He left the cave and was buried elsewhere. The Brachah "Pi Shnayim b'Ruchacha" was fulfilled through healing Na'aman's Tzara'as; this is like Techiyas ha'Mesim, for a Metzora is considered dead.
Malbim: A Tzadik's body and bones are an Aron for Kedushah. Chulin should not touch them!
