Leaving the E.U

Does anyone know how it might affect our current health care in France if the UK leaves the E.U.?

Oh thank you…we have been worrying unnecessarily then !

There is a lot of speculation, but actually leaving the EU is a red herring. If the UK left the EEA then it would be a very different story. The S1 is valid in all EEA countries plus Switzerland. For people who have been or are contributors to the French system it would make no difference whatsoever.