To not want to go to my brothers party?

@Cheekandtongue you absolutely CAN leave your cats overnight . Fresh food and biscuits , water and away you go.

If you don’t want to go then don’t go. But the cat reason is not relevant they are cats they won’t give a damn. It’s literally an hour away- I take my daughter gymnastics twice a week 45 mins away.

Can you say to your brother you’re not a mega party person, and offer to help him set up the party? Bring a great card and a small present and write a meaningful note in the card. Spend some time helping before people arrive. Then you could make an earlier exit at least?

Have you seen anyone about your anxiety?

I’m with you on night driving OP. Hopefully your brother also understands.

Dusk is due about 9.30 next week, a tiny bit later if it’s a nice day, so if you aim to be home by around that time, would that work for you?
You could just be with him for an hour or so or just long enough to deliver a token gift and card. At least you will have made the effort to give him a hug and wish him well for his party. Or ask him if he minds meeting you half way earlier in the day if you really can’t face it. Please don’t keep him in the dark about your anxiety issues, let him understand and help if he can.

By the way, I also completely understand your reluctance to leave your pets. I hated having to leave my cat overnight when she was old and sick, as she didn’t eat dried food so I couldn’t use one of the timed feeders. I used to get a friend to stay overnight but it was always a hassle. Now she’s gone, I’m so glad I didn’t ever neglect her needs. It can be a conflict but sometimes, family has to come first if you can possibly somehow manage it. Always best to try.

Get a pop up feeder for the cats. They would be fine for 24 hours but you don't even need to be away that long.

Absolutely agree

Don’t want to waste the petrol

wow. That’s harsh for a brother I assume you love , let alone seeing rest of family

cats are fine to be left alone for the odd night

auto feeder or big bowls left of food and water

or you pay a cat sitter about £10 to pop in

are you saying you don’t have a single friend , neighbour or work colleague who could pop in to feed cats

that’s a lonely life 😢

anxiety is hard and crippling but don’t let it ruin your life

I’ve driven 3hrs each way before on same day to see friends for lunch /family party for 2/3hrs

a tiring day but worth it

agree chat to doc about how you feel

but go to the party. Cats will be fine

YANBU
Do you never leave the house? Work?
What if you had to attend hospital would you not go?
You think it's a waste to drive? I don't really understand why you said yes.
Your "reasons" sound very unreasonable. Is it anxiety / cats / petrol wastage?

If you don't want to go then don't. However do not be surprised if your relationship with your brother suffers To maintain sibling or indeed any relationship requires effort He's extended an invite to you.

You could put your cats in a cattery, ask your parents if you can take them to their home so you are not away from them overnight.

I would make getting help for your anxiety an absolute priority.

This.

Just don't go. Tell him that it's too difficult for you to go. Apologise, be polite but friendly, and tell him soon. There's no point in fretting about it or making excuses. Just don't go.

It's only a "waste" of petrol if you're driving an hour to do something or see someone you don't want to.

If you don't want to go, you just say you can't make it and leave it at that. Don't justify it to yourself or anyone else with excuses that could easily be sorted - cats are independent enough that if you leave an auto feeder they won't even notice you're gone, and petrol will be cheaper than a taxi.

Don't go if you don't want to. But don't make up rubbish because that will offend people more.

They are cats. Lock them in with food, water and litter trays. That’s fine, it’s one night, that’s perfectly acceptable.

An hour is also not drastic. I drive that twice a month, over an hour out and same back to go to butcher and grocery shop I really like. DH drives nearly 2hrs each way for his favourite pie shop. Some people I know drive more than that each way daily to get to work.

This

Don’t use the cats or petrol as an excuse not to go when speaking to your family because honestly the cats is a cop out and the petrol reason is hurtful.

If you really don’t want to go, explain that you’re feeling anxious around it and could you please arrange something else so you can catch up with them.

Family are important and especially so if you suffer with bad mental health. Don’t push people out or forget about them because one day you’ll need them.

Feed the cats right before you go, and leave some food out. Stay with your parents, and drive home in the morning. The cats will be absolutely fine for one night. Do your parents know how much you are struggling with your anxiety? I'm sure they'd like to support you.

I mean this kindly as I know you have anxiety. But not being able to leave your cats overnight to go to your brothers milestone birthday party is really insulting to him. The waste of petrol excuse is absolutely awful. Please please don’t use that as an excuse. It’ll be extremely hurtful to your brother and parents.
Your cats will be fine overnight, and if you’re too worried about that, hire a cat sitter for the night. Please try to go and celebrate your brother. It’ll mean a lot to him, and I expect it will really destroy your relationship with him if you don’t go.

Edited to add, you should seek help for your anxiety if it’s bad enough to stop you going to special events with close family. That’s extremely restrictive.

If you don’t want to go just don’t go, there is no need to make up excuses.

@Cheekandtongue but it’s not a waste, it’s to see your brother and family on a special occasion and celebrate.
Your cats will be just fine. I’ve left my two several times overnight, I just make sure they have enough food and water and they get extra attention in the morning when I’m home 😀. Always been just fine.

If you don’t go, pull a last minute sicky. Pesky norovirus. Don’t tell him it’s because you don’t want to leave your cats/don’t want to pay for a taxi/don’t want to drive in the dark.

You'll feel better for going, you will!

Your cats will be fine, I leave mine overnight occasionally, just give them a load of food, they'll eat it all immediately and then fall into a coma for about 20 hours.

OP I am assuming you are in your 20s or 30s based on your brother's age. That is really very young to be limiting yourself with all these anxieties and excuses. If you don't like driving alone in the dark, what do you do in winter? If you can't leave your cats for one night that will make life pretty small. Use this important family event to push yourself a bit. It will help you get over some of your current limitations.

If you were my sibling and said you couldn’t come because it would be a waste of petrol or that you couldn’t leave your cats, I would never bother with you again.

That. Not one of your excuses holds water when it comes to your sibling's big birthday.

If you really can't go then you need to be absolutely upfront with your mental health issues. They really are the only half way valid reasons not to attend.

But seriously, you need to push yourself on this one. If you can't get yourself to your own brothers 30th, you need to be seeing your GP, and fast.
But if you push yourself to do this trip, you'll achieve something, maintain your family relationships, and maybe end up with a bit more self-belief.