Hi Pip
Welcome to the forum.
You might want to have a look at the following FAQ which explains where everything is;
www.benefitsandwork.co.uk/guides-for-claimants/faq/forum Short answer to your question is no.
ESA stops when you reach state pension age, if your wife gets medically retired, will she receive any health insurance pension?
When you talk about ESA you need to say what type of ESA are they receiving (IR , CB or NS ESA)
You may want to contact your local Welfare Rights Organisation who can take all your wife's circumstances into consideration to give you accurate advice; you can find your local Welfare Rights Organisation to help you with advice by clicking on the link below and putting in your post code, it will then come up with a MAP with a list of agencies.
advicelocal.uk Gary