This may be an impossible question to answer, but my father, in his eighties, refused a flu shot this year. He said he won't get one because it will make him sick. He has always been diligent in the past about getting one.
Over the age of 65 I've heard a double dose of the vaccine is reccomended. I've had mine but I'm frightened of him getting the flu and leading to pneumonia, and I take care of him. He does get out in public now and then mostly for grocery shopping.
The flu vaccine is the best way not to get the flu and it can make you feel a bit ill for a day or so, but it is very mild.
Do note this, the flu vaccine does not guard you from totally getting the flu, if you should get it, it will just be a milder case. There are too many flu strains to cover all the bases, so they try there best to a give you a vaccine that covers what they believe the current years threat.
My father get his flu and pneumonia vaccine, but due to other underlying medical conditions his immune system is compromised and he has contracted pneumonia and been hospitalized three times this year alone. He has COPD, emphysema, type 2 diabetes (insulin dependent) and host of other problems. All of these problems combined compromise his immune system, so it's very easy for him to catch any little virus that comes along and develop into pneumonia.
I've almost lost him three times this year. Each time he gets weaker and weaker and has developed congestive heart failure from it.
He now has a bad case of bronchitis and I fear that when we return to the doctor again on Friday, it will be pneumonia.
The elderly get more frail the older they get. The more times they develop pneumonia, the worse it becomes. My father will be 77 this year, if he makes it. We don't anticipate him seeing 78.
Bottom line is it's his decision, but I'm currently watching someone die and doing the best I can, because he didn't take care of his health when he was younger.
All you can do, is all you can do.
Prayers go out to you,
Suzanne