"remember my mother crying when John John saluted the coffin"
I was 8 in 1963, I watched all of it hour after hour, from the time immediately after the shooting till the funeral.
I still remember the cadence of the horses hooves, I still remember RFK walking in procession in his mourning suit. It had a profound impact on me.
A 5 yr old will have the memory of the events and as he grows up you can explain the significance of them as his maturity grows.
I had a discussion with my neice many years ago. She was griping about her studies of history. I told her that what she considered history was current events for we old folks that lived through it.
Attending will give your son a historical perspective that he will not have otherwise.
I wasn't born until the late '60s, and all emotion and impact of the JFK Jr.'s salute, etc., while touching, is lost on me in large part. I feel so bad that my infant nephew won't have a clue what it was like to have Pres. Reagan as his president in his lifetime and will have no memory of this week's events.