He's over 65 and has been in the USA for 'over 20 years'. It sounds like he was working and paying tax & national insurance (social security) in the UK for something like 20 years. That should qualify him for a UK old age pension, which gives him an E121, which gets him into the French health system and you can piggy-back off that. What would happen should he pre-decease you I'm not sure, but you might qualify for a UK pension based on his contributions.
You need to talk to the UK national insurance office to find out whether one or both of you does qualify for a pension. If so, then you will be covered for French health requirements.
Karen,
You also need to get tax advice, because as you are aware US Citizens and Green Card holders still pay US Federal taxes even if you are permanently non US resident. Although, you would hopefully get relief under the US/France tax treaty, I believe the US in its wisdom has recently reduced allowances given to US expatriates. In fact if your husband qualifies for a UK State pension you could find that taxed in the UK, USA and France!
If your husband is considering giving up his Green Card, again you must take tax advice, as that it its own right can trigger off US tax exit charges. The US authorities for some reason take a dim view of US Citizens revoking their citizenship or long term Green Card holders giving up their status, as they presume it is to avoid US taxes until proven otherwise.
With regard to your medical situation it is highly unlikely that you will be able to obtain comprehensive private medical insurance in France, as existing conditions and any connected complications would be excluded from cover Therefore, I would defer any final decisions to move, until you are certain you would be covered through your husband during his lifetime and afterwards should you survive him.
Presumably, you will qualify for Medicare in the good old USA when you retire and if so you have the fall back option to return to America?
As your husband qualifies for a UK pension then you will both be covered for standard French healthcare. Normally that reimburses 70% of your costs -- you can take out a 'mutuelle' to cover the remainder. You can also qualify for 100% reimbursement for certain long term conditions, so if you need medication because of your transplant you might get it free.
I'm glad your husband is sorting out his pension; it's not really the sort of thing to leave to the little woman.
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