A patient who dies as a result of the natural progression of their disease, following the refusal of life-prolonging treatment, does not commit suicide. Airedale NHS Trust v Bland  1 All ER 821, Re JT (Adult: Refusal of medical treatment)  1 FLR 48 and Re AK (Medical treatment: Consent)  1 FLR 129
Doctors who are uncertain about how a particular action might be viewed in law must seek up to date legal advice. This can be obtained from a defence organisation, professional association or an employer’s legal department.
See references in Treatment and care towards the end of life. Making sound clinical judgements and Palliative care for adults: strong opioids for pain relief.