Why did perceval’s mother take him into the deserted lands and not allow anyone

I think that the answer is: She had lost her husband and six older sons to war and fighting and wanted to save Perceval from that life.

Perceval's father died when Perceval was a small boy. His father was a recluse before his death. He lived in a manor house in the forest after he attained a would from a battle. 

Perceval's mother raised Perceval on her own. She deliberately kept him ignorant from things that he needed to know for fear of him leading a life that would surely end up in his early demise. 

Montag Stealing books from them