Centralised patch management in and Organisation

Hello Patrick.

You cannot delegate patch management to a different account. Patch Manager is part of node management, and according to the documentation:

When you set up an organization in AWS Organizations, you assign a management account to perform all administrative tasks for all AWS services. The management account user can assign a delegated administrator account only for Systems Manager to perform administrative tasks for Change Manager, Explorer, and OpsCenter. AWS Organizations is an account management service that you can use to create an organization and assign AWS accounts to manage these accounts centrally.

I hope this helps.