Wow, that is a problem!
I remember being a young teenager, maybe 12 or 13, entering puberty, and my ski bum uncle staying at our house for one of his drunken party visits home.
At the dinner table he turned to me and told me I smelled bad and that I should shower and use some deodorant...........
While it was probably good advice, it was the wrong time, the wrong place and definitely the wrong way to tell a young kid about hygeine......
I remember having to drag my two preteen sons into the shower. Now that they are grown you can’t get them out of it. They both take long showers.