Why did he ask the youth to ascend?
Radak #1: Perhaps the youth had not ascended with him to the top of the mountain.
Radak #2: Perhaps the youth ascended with him; Eliyahu told him to go higher on the mountain (so he will be able to see farther).
Why did he ask the youth to look?
Radak (42): He did not want to rise from his Tefilah 1 until he knew that there was a Siman of rain.
Surely 'Techilaso' is a printing mistake. (PF)
Why did he ask him to look Derech Yam?
Rashi: Look for a cloud rising from the sea. Radak - Har ha'Karmel is near the sea.
Radak citing Targum Yonasan: "Derech Yam" is to the west.
Did he tell him from the beginning to return seven times?
Radak: No; seven times, he told him to return, for he did not see anything until the seventh time. Malbim - the Supreme Yam, to which all rivers flow (Koheles 1:7) has seven seas. Due to the sin of the generation, the Shechinah had risen to the seventh Raki'a, so it needed to return seven times.
