What criminal liability would arise here?

Would alfie be liable of ABH OR GBH and why?

Alfie and Timmy are school friends, attending the local Primary School together. Both are ten years old. The pair have a rivalry with another schoolboy, Henry (aged 11) who bullies the pair relentlessly. One day during the summer holidays, Alfie and Timmy are walking Alfie's dog, a rottweiler. Alfie knows that he should not be taking the dog out for a walk himself due to its uncontrollable nature. Alfie also knows that the dog normally wears a muzzle, however Alfie wanted to impress Timmy, so he took the dog out anyway without his parents' knowledge and without a muzzle. The pair come across Henry in the park. Henry, having spotted the Alfie and Timmy, makes his way over to them and starts shouting abuse at them. Alfie, annoyed at how Henry treats him, shouts "KILL" to the dog, whilst pointing at Henry. The dog immediately jumps up at Henry and bites his arm. Whilst Alfie watches the attack take place, Timmy runs up to Henry and starts kicking him in the leg whilst Henry continues to be attacked by the dog. A parent (Mr Pearson) witnesses the commotion and is able to remove the dog from Henry. However, Henry has suffered serious injuries to his arm and face, including cuts, scratches and several large puncture wounds caused by the dog's teeth. Henry is transported immediately to the local hospital and is seen to by a junior doctor, Dr Bear. Dr Bear is exhausted from having worked for 36 hours without a substantial break. Dr Bear meets Henry and administers him with pain relief. Dr Bear then leaves Henry in a hospital bed, intending to return later in the day. Henry's wound has not been cleaned and becomes infected. The infection spreads quite rapidly, and Henry dies from toxic shock, brought on by the infection.