Do we write du or ni to patients?
Du, the singular "you", and never "patienten", the patient.
Writing to one person puts the reader in the sentence as the one who acts, where the third person turns them into a case the text is about.
What this answer rests on
baseline/voice/1-den-nara-experten-karnguid.md§ Snabbreferens Acceptedbaseline/voice/1-den-nara-experten-karnguid.md§ 1. Patienten är subjekt, inte mottagare Acceptedconstitutional/voice-is-the-present-expert.md§ 4. The non-negotiables Accepted