We can’t judge for hair thickness without measurements. To say if someone has thick medium or fine hair we have to measure the donor hair caliber. I can’t see any measurement about hair thickness and they don’t even mention that he has fine hairs. So that’s your opinion based on an assumption which might be wrong.
In general Even if someone has fine hair, the surgeon plan to implant more grafts in order to give good coverage with one procedure. That’s why they do measurements before the procedure to do the best plan for good coverage. He could easily do it in one sitting as his area was quite small.