weird to think he was less than a decade older than my parents - he seemed a thousand

Oh gosh, that's sad. His son's an old chum of mine. 

i went down a bit of a rabbit hole as I couldn't understand why he'd inherited the title when he was the second son.  turns out nobody understands it:

This novodamus for this arrangement embodied a unique remainder, the effect of which was that:

1. the titles would pass to the heirs male of the 1st earl's younger sons before the heirs male of his eldest son (who was heir apparent to his mother's Dukedom of Hamilton);
2. if the person who would otherwise inherit the title was already duke of Hamilton (or would inherit that dukedom at the same time), the titles would pass instead to that duke's next surviving brother;
3. if the titles were ever held by a duke of Hamilton (either because an earl of Selkirk succeeded as duke of Hamilton, or because provision 2 was unable to operate because the heir was a duke of Hamilton who had no surviving younger brothers), the titles would pass on that duke's death to his second surviving son;
4. if the titles had passed to a younger brother or younger son under provisions 2 or 3, they would then pass to his heirs male on his death; but
5. if such a younger son or younger brother's heirs male died out, the title would not pass to his own younger brothers and their heirs male, but would instead revert to the senior male line, with provisions 2 and 3 operating as before.^[3]

This remainder is so unusual that a Scottish country dance—Hamilton House—was created around it.^{[citation needed]}

Bloody aristos. Lords in the HOC.