I thought the very same thing. Granted, the chances of transmitting HIV through saliva are low compared with saving the life of a child. He could be slammed with anti-virals after the fact if the LG was forthright.
And yes, he should be subject to review and disciplined or fired for not having the requisite equipment to do his job. It's like a LEO going to work without his sidearm.
In many case these lifeguards are just high school kids who do not give a hoot about "reviews" or being "disciplined". Probably he will not show up at work in that place again.