There is an abundance of different travel insurances tailored to the senior citizen.
Here are just some of them:

Age Concern Travel Insurance
With Age Concern Travel Insurance, there is no upper age limit, and you can cover your pre-existing medical conditions wherever possible. You can choose a Single Trip policy for one trip, or an Annual Multi-trip policy if you are a regular traveller.


Senior travel insurance from Globelink
Senior traveller insurance for persons aged between 66 to 74 travelling on package/self-catering holidays with durations ranging from 5 to 31 days.