To clear out the damage with the roots and prepare it for its new life, I basically had to bare root it, remove the damaged main root at the base of the tree, before placing it in good quality mix and a slightly larger pot.
This species is pretty much impossible for me to replace and this was the only one available (not on display) and it was only offered because I inquired. So I really want to keep it alive.
It arrived with only a couple of large leaves which looked average anyway and consequently dropped post re-pot. The structure that is there is still green. No further damage is going to be done to the tree, so I'm hoping this is a turning point. It doesn't appear to be browning off at the tips or dying back.
I need your help in how to keep it alive ...please!

It typically is a semi-shade to full sun plant. Kinda similar to Ficus carica species.
So, do I keep it in the sun? Semi-shade? In the shade until it recovers?
I assume I just water to match the sun conditions. But should I greenhouse (high moisture) environment; treat it like it's a cutting?
Is there anything I can feed it to help it recover its vigor?
My last and drastic option... it has a base and two long branches, do I turn the two branches in cuttings and try and get them to root and just pray the base or one of the cuttings makes it?