He’s not that ‘acutely’ limping/hopping lame, like a sprain. More like an ache, or like both his feet ache. Like the video. Normally I can’t stop him on the lunge... And today I’d be prodding him to get him to trot.
I don’t think you need to panic. Hard not to do, I know. Try to keep him comfortable until the farrier gets there and just pull his shoes. See what happens with that.
Didn’t he wear pads for a long time until fairly recently? You might think about going back to them - ask the farrier what he thinks.
We’ve got a couple of horses that can not go barefoot in the front (and we don’t have rocks), they just have tender feet. Farah is one, no riding, nothing but lounging around but she goes lame without front shoes.
I sure hope he gets better rapidly, I’ll be praying for that. Winter is hard enough without going through it sore.