Why did Graystripe not become deputy when he returned to ThunderClan?

Well it depends on what timed he returned to ThunderClan when he first comes back from RiverClan Whitestorm was all ready deputy. But when he came back from being captured by twolegs the clans had moved to a different home because the twolegs cut down the forest, he was tired and so was his mate Millie Graystripe told firestar that he wanted to get to know the land before even thinking about becoming deputy but graystripe is deputy at the old forest before the twolegs captured him and cut down the forest. Firestar makes brambleclaw deputy after they cant find graystripeand move to the lake.