Is it fixable? Yes, in the sense that you can rip apart everything to get to the damage and repair what’s broken. Is it worth fixing? I can’t answer that for you. What I can tell you is in 2017 I had a few things to check out and fix on my 2004 Rockwood. The sewer connections got damaged by a large bump on the highway and was hanging down, grinding away on the road. (I had flushed the tanks out and was taking it to my brothers house to store over the winter) Spring of 2018 I go pick it up so I can work on it. I took a week off from work and figured I could get it fixed in that time. I’ll spare you the details, but last year we took our first trip in our newly renovated camper. Consider your options before you have a trailer that can’t be moved until you fix it.
There’s no such thing as “a little bit of damage”. Whatever you can see is just the tip of the iceberg. I’d imagine if you can see that much drop in the wall, the actual damage is much more widespread and will most likely go up into your roof. Damage to a structural support is something I wouldn’t want to try and deal with.
My suggestion is to see if you can get anything for it on a trade in for a new camper.