If the fire wasn't too hot or lasted too long, the damage might not be so severe. Bark is a better insulator than one might think. In case there IS damage, it might sprout anew lower down from epicormic buds underneath the bark.
Eucalyptus thrive in these settings and since many oaks live in dry, fire prone settings (Cork oak for example), I wouldn't be surprised it'll come out better than you expected.
Keep it watered (at the soil) and don't do anything this year. Wait until the next growing season to see what'll leaf out and what doesn't. Then you can begin reshaping it if you so wish.
