I am truly an old geezer. I once met a man who knew (met) Lincoln. He was, of course, a little boy at the time. I met him when he was a docent at the Lincoln Memorial in Springfield Il. right after it opened. Talk about “degrees of separation”.
There is coincidence in regard to Lincoln and presidential assassinations. He was either present or was nearby when three of them occurred.
Of course, any other person with similarly close access to presidents and with such active involvement in the Federal government during that period of 36½ years would have had a similar likelihood of being "at or near" these assassinations. However, it is interesting that each time, his presence had been requested by the President in question.
In another odd coincidence, Robert Lincoln was once saved by Edwin Booth, brother of John Wilkes Booth, from possible serious injury or death. The incident happened at a railroad station in Jersey City in 1863, when Robert was traveling from New York City to Washington, and was recounted by Lincoln in 1909.