"Refusal of medication because its 'too expensive'"

My dad suffers from cluster headaches and is extremely poorly with them for a short period every year, usually lasting around 6 weeks. He has frequent excruciating attacks and is also under a neurologist at Sunderland Royal Hospital. He has to have sumatriptan injections which is the only thing which takes the unbearable pain awa. He also has a supply of oxygen at home which he can use to stop the attack progressing if he catches it in time. The doctor in this practice has openly said he cannot be prescribed any more injections due to them costing the nhs so much money and therefore effecting the practice budget. It's disgraceful, the neurologist has had to call this doctor numerous times and demand that they prescribe what my dad needs.