A raptor foster relationship?

I could not believe it when I saw this smaller bird flying after the bigger one which I could make out immediately to be a Crested Serpent-eagle.  It took awhile to locate the birds which I was hoping desperately would still be around.  I spotted the Serpent-eagle first.

And then the smaller one came into sight.

And just as I had guessed, it's the sub-adult Crested Goshawk.  

And strange enough, it kept flying around the big one as if trying to get its attention although it did keep its distance.

The Goshawk flew and perched from one spot to another but there was no response from the other.

And the Serpent-eagle remained at its spot all the while.

The Goshawk's behaviour was difficult to decipher.  It looked like this bird is now left to fend for itself as I've not seen any of its parents anymore.  Could it therefore be trying to seek a foster parent, if at all juvenile raptors do that, and of another species?
Why would this Goshawk try to get close to the Serpent-eagle?

The Serpent-eagle was totally unperturbed by the presence and movements of the smaller bird.

Again the smaller bird looked like it was trying to get close.

And this was the closest the Goshawk got to the Serpent-eagle before the bigger one flew off followed after by the smaller one.