So, your mother-in-law is turning eighty years old, and your spouse has decided that they would like to throw a birthday party for her at a little Italian restaurant over by her house. This is a perfectly reasonable thing to do, since your spouse has never thrown a birthday party for her before, and this might be the last time that you can get all of the old ladies together before they fall and break both their hips, or get dementia and get sent off to a home. You are supportive of this idea, because you like your crazy old mother-in-law and think it would be fun to have a party for her.
In order to up the ante on the party experience, your spouse has decided to make it a surprise party. This means relying on all of your mother-in-law's old lady friends to keep a secret for a few months before the party, and also running the risk of giving her a fucking myocardial infarction as you all jump out and yell "surprise!" at her after too many cups of coffee. At this, you will ask if it is really such a good idea, and then eventually be convinced of it after a few glasses of wine one night.
You might be curious how to manage all of the different variables inherent in helping your spouse host a birthday party for your unsuspecting mother-in-law. What are some good ideas, and what are some common mistakes? Why does your spouse make that weird whimpering noise after learning about the second or third dead person they have accidentally invited? How much booze should one try and foist on that woman with the tennis balls on the feet of her walker? Hopefully this writeup will help you untangle some of the mysteries.
...suggest that the party should actually be a roast instead. Nothing would be funnier than the idea of your poor mother-in-law sitting on stage while a bunch of her friends take a microphone and mercilessly make fun of her. You can even make a list of which b-list celebrities you would invite to lay into your mother-in-law, and bring them up one by one when your spouse starts freaking out about the party. It will relieve stress for both of you, and also slightly increases the chances of actually convincing them that this is a brilliant idea.
...go and help pick out the party favors. The last thing your spouse will want to think about is what the hell they are going to use to hold all of those M&M's they ordered with your mother-in-law's face painted on the candy shell. You might be able to convince your spouse that those little glass jars will work much better than the chiffon bags they were looking at in the last aisle. You can also give your opinion on the little ribbon to tie around the jars and everything, and you will be a hero or something.
...drive out to the restaurant the day of the party. Your spouse will be dressed up in formal clothing and stressing out about the party anyway. Not letting them drive will keep them from ramming into a guard rail and thus keep you from having to go to the party. It is better to just go and get it over with than spend an afternoon in the emergency room, so just get behind the wheel already. Your completely intact bones will thank you later.
...help that one old lady get food from the buffet table. You will be the hero of the party if you grab a plate of food for that one old woman who doesn't seem to be getting around all that well. Bonus points if that one old lady happened to, say, fall down earlier that morning and is only at the party due to the effects of very powerful pain killers.
...go get the car and pick up your mother-in-law at the door of the restaurant. Because she has had two knee replacement surgeries already, and the fewer steps she takes now means the longer she can go without getting them replaced for the third time. This will also allow you to turn the air conditioning on in the car before she gets in, and then she won't sweat like some kind of electrified sweating machine while you drive her home.
...help her haul all of the presents up the flight of stairs into her house. Look, she's not going to be able to carry that planter with the ugly-ass fern in it up those stairs by herself, and you're standing right there. And your spouse already has their hands full with the bags of other presents as well as the leftover M&M's they couldn't fit into the jars. You probably need the exercise anyway.
...allow your spouse to over-think the birthday card. Your spouse doesn't even need to get a card, what with the whole inviting everyone to the fucking party and everything. You won't be able to convince them to not get a card, but the least you can do is walk down the card aisle and prevent them from having a self-induced psychoanalysis session in the middle of Walgreens. Tell your spouse that they one they have in their hand is absolutely the right card, and get the hell out of there already.
...drink so much fucking coffee right before the party. You will get hopped up and maybe a bit more animated than you would like, and then suddenly you will find yourself cursing loudly in front of some children or something and that will be really embarrassing.
...suggest doing shots. Really, your spouse will not find this as funny as you would think they should. This will only bring forth feelings of desperation and regret in your spouse, as they wish they could drink away all of the problems this party has brought up for them. Additionally, some of the old ladies might not like the idea that you would like drinking those devil spirits, and then you will look like an asshole.
...let that one little old lady sit by herself. Maybe she doesn't know anyone, or maybe she's your spouse's aunt or something? You might not know, but it is your job as support personnel to go over there and talk to her. Chances are she has forgotten her hearing aids at home, so you might have to talk at an uncomfortably loud volume the entire time. It is okay. That woman will appreciate what you're doing.
...hang around your mother-in-law's house after the party. The shock of the surprise party, as well as talking to all of her friends for a few hours, has completely exhausted her. She wants you to leave so she can go to bed for a few hours. Just kiss her on the cheek and excuse yourself so you can let her get to it already.
When you're all done, you and your spouse can go home and take a nap for the rest of the afternoon, happy in the knowledge that you have made your mother-in-law happy for a few hours. And then you can get up and start planning her 90th birthday party, because she will totally outlive all of you and it is best to start planning ahead.