fixable?

Hit or walloped

Is he ok ?

If it was a vertical pole and it is still vertical after going that far into the front of your car to leave the bonnet like it is, then you are looking at a radiator, bumper bar and a few other bits, fixable it is, how much it costs depends on the damage underneath the bumper.

Two facts:

1. Everything is fixable,
2. Everything is not worth fixing.

Is it just the bonnet?

As said it is "fixable" but its still toast. Insurance would write it off for sure. Even if using second hand parts and willing to drive around with odd coloured panels, 1980s style, it'll cost comfortably into 4 figures. As well as the obvious bonnet, slam panel and bumper bar, possibly lights, other bits and pieces, there could well be damage to the subframe or longitudinal members = it's bollixed

You’d definitely get the parts from a scrapyard if you didn’t want to go through insurance. Would look a lot better than trying to fix that bonnet