I definitely think his use of renewable energy is a great step forward.

The trouble is that he seems to keep a lot of ruminants for the amount of land he has. Ruminants produce very potent greenhouse gases that are not offset by sequestration (cited a few times in other sources), so with that plus all of his other animals kept I'd be very interested in independently gathered data (i.e. not marketing materials he wrote himself ) about the GHG production / absorption by his land.

Sadly, I'm struggling to find the number of animals he keeps or anything I could use to run any sort of calculation.

Therefore, this definitely looks like the closest I've seen to sustainable animal agriculture, but its claims are currently unsubstantiated.