Here's the thing: late developers are where NOTHING has happened by the time you are 15 or even 16, as with my younger brother and a school friend of mine at the time. The first year is all internal, anyhow, as your body goes about making chemical hormones to bring out all the changes of puberty. Whilst your bathroom situation is a lil unusual, I do know of family 'traditions' that can start when one is young, and carry on through puberty.
For e.g. a family I know has always had a "Sundays in bed" from when the children were small; in their jammies.... and yes, it happens today, with them all as adults, on the rare visits when they are all together at the same time. But I wonder if your uncle's bathroom ritual is sexually motivated?
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.