I had to read up on these folks to understand that one of them was shot dead at 20, and the other attracted tuberculosis and died at 26.

Pretty sure you mean "contracted" TB, but the typo did provide a humourous mental image.

I probably did. ESL, in over my head.

Your first clause is complex and correct so you're doing just fine. :)

...so even at the end of their lives they would have still easily qualified for the Fields Medal. Maybe they should receive a posthumous honorary one. Or maybe they already did?

Yes I think Galois deserves a Fields in his name

Well, not the same, but Galois did get fields in his name, actually https://en.wikipedia.org/wiki/Galois_field . Is that what you intended?

Yes, that's the joke ;)