Have you gone to the top of the tree and scraped off the outer bark to determine whether it's dead there ?
With a bit of luck it'll just have shed its leaves and be dormant inside.

I have one here, about 5 years old and mine looks decidely ill when it's under attack from aphids - it looks like it's dying.
When this occurs i spray it with Provado insecticide and it rallies round to be as good as ever.

It also suffered, in its first two or three years, if it was too dry - i'd water it copiously and it came back. I'd trim the top couple of inches from it but then leave it alone.

Fremontodendron californicum seems to be quite a difficult plant being quite short-lived and can die for no reason. I would treat it with respect as the hairs on the leaves can irritate the skin and can be dangerous if they get into the eyes. Strangely enough my local garden centre refuses to sell it.

There are numerous plants which are deemed to be poisonous or irritant but to shy away from them is wrong, common sense prevails to most.