Ohh i dono what to do i just want to say im sorry for you because it probably effects you and poor dude he misses hes kid :( im sorry.
He is unsettled by the loss (relatively speaking) of his father, and this in itself is normal. Thatis, he is responding in an understandable manner to a difficult situation. Hopefully you and his father can establish a more frequent plan for contact. After all, you are not living that far apart. The focus should be on the priority of parent/child contact, not on the distance.