Why would you want end users, senior citizens or not, to mentally parse URLs?
The rule is: If the bank, or paypal, or your landlord, or anyone else really emails you that you have to complete some information to your account or pay the latest bill or whatever, you GO TO THEIR WEBSITE and login normally. If it is important they will have the same information there.
The same rule also applied to unsolicited phonecalls, but it might be harder to follow: If your bank, or the police, or some other important person calls you and asks for information or for you to do something that feels the least bit off or hurried, you take their contact information, you look up whatever it is they want you to do and you CALL THEM BACK at the official telephone number of the bank or the police. You probably already have the number and if you don't it's on their web site. Do not call back on any other number.
People working the phone generally have much worse protocols than people working over email, so they may be less prepared for you to do this, but I have never heard of anything important that was emailed that wasn't also easily available when logged in to the website.
The only time it is appropriate to click a link in an email is when you are verifying your email address with them. Not for any other reason.