The brown spots look like sunburn, and will not go away, but new leaves will grow. Have a look at the roots, is it potbound? Do the roots look healthy and not rotted? If the pot is filled with roots, he will need a larger pot, but not too large to begin with. New soil, careful watering, bright light but not baking sun. Long naked branches may be pruned back. I am sure a little TLC will help the poor guy recover.

I would put the plant outdoors in open or dappled shade, or in a spot where the plant gets morning and evening sun, this, in order to boost the plant's energy reserves so it will tolerate the stress of repotting it (not potting it up) we/o languishing half the summer. Potting up allows your plant to improve growth and vitality - a little, so the plant is growing a little closer to its potential. Repotting, properly done, removes ALL the limitations imposed by root congestion and allows the plant to grow normally, within the limits of other cultural factors that have the potential to impact growth and vitality.

Let me know if you'd like to know more.

Al