Yes, as long as you fill out the movement forms as per a normal sale, the rest is his responsibility.
I am still interested in how he should discharge that responsibility though? We've only ever done one home kill (in the same circumstances, with a tup who had got a bit too feisty). I just wrote 'dead' in the flock book, and we incinerated all the bits we didn't eat.
Might that land us in trouble during a farm inspection though? (because we don't have a receipt for disposal).