I’d offer these important factors to consider:
—How large is her circle of friends? Does she frequently talk, lunch, shop, and hang out with 30 people and send out 200 Christmas cards to all her old school pals and 50 relatives, or does she consistently mention the names of only two or three people and rarely see them?
—Do her friends know each other?
—What (outside the household) is the focus of her world? work? church? volunteer activity? What does she talk about the most, and in which places are the people she mentions most often (and favorably)?
—Does she enjoy other people’s parties?
—The last six times she went out for some event other than with family members, what were they, and who did she go with?
Maybe it’s obvious that your mother is an outgoing life-of-the-party type, and you can get any twenty strangers together and in ten minutes she will have them all at ease, laughing and talking together like old friends and falling in love with her. That would be my old friend M~.
If you asked the above questions about me, on the other hand, you would discover that I have one steady operagoing friend with whom I have expensive dinners before the show, one steady moviegoing friend with whom I have modest dinners after the show, and one workplace friend whom I see outside of work for dinner once a year. And they know one another only slightly. I relate to each of them differently, so putting them together could be awkward. Aside from a few long-distance friends, the rest are so casual that I don’t have their phone numbers. So—if I were your mother, small party.
The worst thing would be to give her cause for embarrassment or pain, so please be sure you know what you need to know. After you’ve settled on the right scale and tone, come back and ask us for specific ideas.