I'm going to have to agree with the health/condition point over age thing. My recently late mother was one of two out of ELEVEN siblings to have left Ireland for England, spending her entire adult life there and would fly/sail over to visit at least once a year, if not more, from wherever she was (since 1999, it was Liverpool)
As time went on, her health deteriorated to the point of making assistance boarding and alighting fundamental to her being able to make the short trip across the Irish Sea, just consider she passed away at 54 and had declining health for almost a decade. Despite being on her own as well with failing eyesight, even though by the end of it she relied on help from taxi drivers in Liverpool (who were always willing to help anyway) and airport/easyJet staff (she was never the kind of person to want to rely on/inconvenience anyone), she was a resilient woman who still managed to get over enough before finally moving over there for her final days. It was hard for her but still did it no matter what.