Used Trucks Washington State Can A Drug Addicted Mom "kidnap" Her Kids?

Can a drug addicted mom "kidnap" her kids? - used trucks washington state

My brother and his wife have split for some time because of his addiction to methamphetamine. It uses needles. He took his children in Washington State and recently tried to bring his wife here, to help try to clean, too. He did not go to Alaska and send commands back here and then he was gone, picked up his truck and children. What can we do?