Imaginary Friends

Liz • *Married to my wonderful best friend! Have a handsome 6 yr old and currently pregnant with my 2nd❤️
My son has this imaginary friend. About 2 days ago he woke me up to show me his imaginary friend, at about 3 in the morning. He told me to say hi to his friend, I was too tired and told him later, and to go back to bed. He looked at me all serious and told me, mommy he made a mad face. Do you all think imaginary Friends are actually ghosts?