We adopted a lovely son at six too also from an asian country. I believe he tried hard to bond with us, but could not. He had lived in an orphanage for six years and no adult had ever tried to make him feel special. He had blunted emotions and always felt different. This is soooo different from my daughter whom was adopted from korea as an infant...she bonded fast and considers herself koresn american and we are very close.
I also have two children adopted out from the u.s., also very young, and we are very close. Do you have other children?
It is not your fault that a child by six did not bond with you. Mine did not either. He married a woman of his culture and does not see us. I understand and am not mad and no longer sad.
I can not tell you what your son will do. I hope he comes back.
I have concluded that six is often too old forba child to bond with new parents although I am sure there are some exceptions. Most will have serious attachment issues that they developed way before they met us.
I hope your ending is different than mine. I do think the later age adoption plus leaving their culture for ours is very hard. I wish id thought of this before doing it, but I thought our love would be enough. It was not.
Hugs to you and trust me when I say I understand and wish you the best. But we do have to let them go if that is their desire. We have no choice.
Therapy may really help you.