Is my mulberry dying?

Trying to save this tree, which might be some kind of mulberry? Indoor hothouse, sandy soil with drainage, soil has become hydrophobic so i believe the plant hasnt been getting enough water for ages. Lots of aerial root development (thirsty?) and multiple shoots from base (response to shock/attempt at self preservation?). Leaf matter but hardly any compost or mycelium. Leaves still green and healthy looking, but lots of dead brush underneath. Cant use fungicides or chemicals that could disturb insect breeding patterns in this indoor conservatory. My first thought is to get a load of high quality organic compost around the root zone. Anyone with similar experience, ideas?