Secretrebel, in many cases, an elderly person is emotionally fragile, especially considering the myriad health problems they face. This aunt is in a position of giving up her home and her independence.
I don't know how old you are or if you've ever had close elderly relatives, but imagine that someday you will be in this aunt's position - you're elderly, you're infirm, you're facing having to leave the home you lived in with your husband or wife, raised your children and experienced many moments of happiness and sorrow. You now have to move into an assisted living situation, among strangers, including those to whom you will have to submit in order to assist you in the most intimate physical details.
Since you'd be leaving your long-time home, you want one last intimate gathering of your family, as a good memory for them and for you to hold on to as you face the loss of your home, your independence, your health and your dignity. You want your family to remember that one last good day as you were, instead of the person you are becoming. However, since you are elderly, infirm, and emotional about leaving your home, you want this to be confined to your family, so they won't judge you.
Now, imagine, you are prepping for this last meal with your family. You've set X number of places at the table, and it took you longer than it had previously, because the extra leaf in the table is almost more than you can handle and it took a good deal of effort to pull out X place settings and wash them by hand. The turkey feels heavier than it used to, your hands hurt more when making the pies and mashing potatoes, and your legs and back hurts more from standing than it used to. You're tired, you hurt, you know this is the last Thanksgiving you will ever host. You're going to try to keep it together, but if you break down, it's just the family and they understand.
Now imagine, your nephew Larry shows up with some girl, a total stranger to you. Now you need to rearrange the table, pull out that extra place setting, find the extra chair that you had put in the garage to be sent off. Now you worry that there might not be enough biscuits, potatoes, or pie since you only made enough for X number of people. Now you have to "perform" for a stranger instead of relaxing around family.
Now, Secretrebel, whose feelings would you place first, the elderly aunt who is experiencing her last Thanksgiving as a independent host, or Larry, who has many years left of Thanksgivings he can spend with his girlfriend(s)?