Since you have a clear cut case and provided you have all the requisite documents available, you can apply in France for the sake of convenience while it does take more time to get the approval.
Vietnam is another good option for fast approvals. Usually is less than 10 days in Hanoi.
Given that it's for medical reasons, they will be considerate for sure.
Example:
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Best for health to you! Stay strong 🙏🏻