I think it is more appropriate to contact the rep's employers than to speak to him yourself.
Part of the maturation process that turns us from children into adults is learning the concept of 'time and place'.
We all like the odd inappropriate joke, we all swear occasionally, or even frequently, but not in front of our children or loved ones.
This lad has obviously not grasped that a coment that may be funny in the bar with his peers, is not funny to family holiday makers, and this should be pointed out to him, and that is the job of his employers.
If you make your point in those terms, the employers will understand the issue you are raising, and hopefully he will get some firm advice about relating his language and humour to the company in which he is operating.