Locked Macbook Pro
My brother give me his macbook 2019 model as gift which was under use of his apple/ICloud ID. i use this laptop for 3 months with my apple id and suddenly device got locked bcz he sign out Apple Id when he gives to me but forget to remove from ICloud.com/ device. After this he removes this device from his ICloud also but device is still locked. From applied.apple.com this device still shows on my apple ID. Please advise how to reactivate the device because now this devise is no longer shown on his ICloud.
MacBook Pro 15″, macOS 10.14