First off, how did it get bent like that? (It looks to me like it was bent in one direction and then bent back the other way, thus the cracking on two sides and the kinked metal.
If the tubing is sound otherwise, as in not rusted thin from saltwater exposure, I'd go ahead and replace that length of tubing.
Look for scaly loose rust inside the tubing and any rust that perforates the tubes.
While tubing can be cut and spliced, a bend like your showing us there will affect too much of the total length of the tube and any such repair would leave you with a tongue that's too short. Besides, the proper fix is always to replace the entire length of tubing. If it were just one end that was bent, it may have been justification to add a folding tongue coupler.
Its up to you to decide whether the trailer is worth the cost and labor of changing the tongue vs. just finding another trailer.