Yes he can he is a spirit being and there is no distance in the Spirit realm.
There are two kinds of spiritual beings(excluding God and man): angels and demons.
It is obvious from the behaviour you have described above that that boy is not an angel and therefore is most likely a demon. Because dead people either go to heaven or hell when they die, they don't stay on the the earth for long.
You need a human body to function on the earth,that's why both God and the Devil work through human beings e.g jujumen and pastors.
So since you say you are a Christian, then you have authority to bind any spirit that is worrying you.
Just say " In the Name Jesus, I bind you and i command you to go from here and never return"
It cannot say no. Don't be afraid.
The only requirement for this to work is that you are a true born again Christian.
And all you have to do is say "Jesus you are the Lord of my life and i believe that you died for me and rose again. Come into my heart. I am born again. A child of God. Amen"
Then ask Holy Spirit to come and live in you.
Then command the boy to leave you.
If you need more help visit a Bible and Miracle believing Church like Christ Embassy