The main thing every elderly couple getting married needs is to understand, is that every state has default rules for how spouses must be treated in an estate plan and in medical decision-making. This means that any current estate plans need to be reviewed and changed to account for what the couple would like to do with their estates. Advanced medical directives and powers of attorney might also need changing as well.
Elderly people can and do fall in love with each other and get married, just like anyone else. Life does not end when people reach a certain age. However, those who do get married later in life, should consider meeting with an estate planning attorney to create an estate plan that fits their unique circumstances.
Reference: Wealth Management (May 1, 2018) "Never Too Old for Love."