Showing Beyond The Fence (Suburban Magic) by Lewis Cunningham

Eleven year old Avery and his 7 year old brother move into a new house. Avery finds himself feeling strange and unable to explain it. After he has several encounters with a goblin, he learns that the forest beyond the fence houses a doorway to magic. Avery's feelings of unease are caused by his sensitivity to it. He can wield magic, if he learns how.

During an encounter with the mysterious Dream King, his pet becomes a person, his brother becomes a barbarian and one friend can fly. The people in Avery's life, from family to friends, start acting strange and are getting sick. He has to do something before things get worse. Who do you get advice from when you need advice about magic?

It's up to Avery and his faithful husky to stop the Dream King, and Avery is not sure it's a battle he can win.