I was a sprinter and hurdler in college. I attended on scholarship but no where near as fast as Bolt. I do recall I would often be the only White guy in a sprint or hurdles race.
Tracks really make a difference. We had an asphalt track and that is mostly what we ran on. I remember one year at the Florida relays they had a new track which was very spongy. It was so different that it messed up my steps between hurdles. I was able to maintain 3 steps but had to chop my steps just a bit.
On an asphalt or even dirt track, my steps came just naturally. That is why most hurdlers are around 6’1” or 6’2” and have a 31 or 32 inch inseam.
That’s damn fast. I tied the school record for frosh soph that my dad set at 10.3 When they went metric they froze the old records. He’ll have it forever!
I think it's still really fast. Ok, maybe not Usain Bolt fast...but still.
Add 25 ft to what your brother would have had to run. He’d probably run 300m at around 10.7/10.8 secs assuming no lost of velocity in that extra 25 ft.