Okay so you would have left his toe longer? He did get a pretty aggressive trim this time to try to get rid of as much of the dead/rotted material as possible.
Like I said, need different angle pix & such to have a more accurate idea, but if your dad only scraped away loose, dead sole, yeah, that's OK, but if, as it appears, he rasped into the sole plane, that's not. That's not how you 'shorten' the toe & if it's too long because of 'dropped' soles then you need to *facilitate* the hooves *growing* shorter gradually, by driving the internal structures higher over time, not try to force it by just trimming the bottom off & further thinning the sole.
But what many people mean by 'shortening the toe' is that it's flared forward & *walls* need backing up - you don't shorten it on the ground surface, past the sole level.
The gauge we used to try to help us get him balanced.
Yeah, tried to explain it's not a good idea to cut to certain angles or preconceived 'ideal' measurements. It can be interesting to gauge the changes in the foot over time by measuring lengths & angles though.
He trims his horses for boots so I think that is why he is getting into the live sole.
Nope, that is no reason. It shouldn't be done, regardless what you're putting on your horse's feet.