To not want to go to my brothers party?

The tell them
a) you can't afford the taxi
b) you can barely afford the petrol
c) about your anxiety issues
Do not mention the cats

If I were your brother I would be upset and offended if you dont come. Your excuses sounds just like that - excuses.

If you absolutely can't drive there and back on the same day, and so worry about your cats, take them with you (but i imagine they cant go into car, parents are allergic and live in a tiny flat and there are so many other reasons why you cant do this).

I think if you really wanted to go you would have found a way.

If you do not go please be truthful, that you are deeply unwell and unable to come. And use it as a point to start addressing your mental health issues, they have become so severe that it is limiting your life to the point you are isolating yourself from your family. The cats and the drive and saying it's wasteful to drive to see your brother on his 30th are unreasonable distractions that will cause hurt if you say these are the reasons. I hope you are able to seek help and get better, it sounds like you are in a bad way 💐

If you don't want to go don't go , just say you can't make it . You don't have to give a reason . Cats will be fine to be left for one night. So it sounds like you are just looking for excuses not to go

It’s not that far and the cats will be fine. It’s harsh not to go unless you dislike him.

Do your family understand the level of anxiety you’re dealing with or do they not see it because you don’t maintain a relationship with them through regular contact and make half arsed excuses such as not being able to leave the cats, not liking driving when it’s dark or it being a waste of petrol to travel 1 hour each way to celebrate a milestone birthday with a sibling who specifically invited you?

I agree with other pp that said you need to look at getting support for your anxiety and suggest you’re honest with your brother/parents why you don’t want to go to the party otherwise there will come a time when a) they’ll stop inviting you to events and b) won’t be there to help you when you need help because of your anxiety!!

A "waste of petrol"? Why do you have a car then? I would have thought this was exactly the sort of situation where being able to drive and owning a car prove their worth.

I appreciate that you are feeling very anxious, but to anyone else your excuses are sounding very weak. If it’s at all possible I think you should go. Your brother might reasonably find it hurtful if you don’t.

seems like a waste of petrol to just drive an hour away for a couple of hours just to drive another hour home

With your kind of thinking, it's never worth doing anything ever because you'd rather stop in with your cats. Honestly, I'm not big into parties myself, but using cats as an excuse to miss your brother's party one hour away is ridiculous, and anxiety only gets worse by avoiding things and assuming you can't cope. Imagine if you got yourself there and back and you and your cats were just fine. That would be a big step in getting out of the sad anxiety hole you're stuck in.

She also said that if she drove over and back in the light that she would be okay. She is using the waste of petrol as an excuse. Saying its a waste of petrol to go and drive an hour each way for your own Brothers big Birthday is just a bit shit.

You will have to think of a better reason to tell him why you’re not attending

Wtf? 🤣

Op how would it feel to tell your brother the stress you are feeling and pressure (I am sure your family are already aware) and perhaps go for an hour at the beginning as a compromise? You always have the option to stay later if you are enjoying it or even leave earlier. Showing up is important, but let them know you can’t stay for long. They will appreciate the gesture. Ensure your buy or make a lovely
gift too.

You could also ask for anti anxiety medication for just a day or two, they work very well.

I think you seriously need to address the real root of your anxiety, because this isn't really the cats and this isn't normal. Do you never leave the house?!

You mention driving - why would you need to spend the night anywhere or fork out for taxis? You drive, stay for a couple of hours and drive back, surely?

Your excuses are just that, excuses, not valid reasons not to go. I don't know the level of anxiety you have, though it sounds bad. Personally I don't believe in giving in to anxiety, if at all possible, because it just makes things worse and you end up shutting yourself into a tiny box where staying home is the default thing to do. IME doing the thing I feel anxious about usually turns out fine anyway.

If you were my dc, I'd encourage you to go.

Sorry about the derailing OP. I hope you find a good solution and help for your anxiety.

Can you not get the train?

Why I am unhinged and unpleasant? What tactics am I trying? As a mother to a very anxious child I’m trying to explain that having anxiety isn’t pathetic.

I absolutely agree - you're making three excuses not to go - quality of the light, waste of petrol, the cats... it's nothing to do with any of that, because the truth of the matter is that you don't want to go. And it's ok if you don't want to go, lots of people struggle with socialising for a range of reasons. But if you are making so many excuses not to go to a significant family event then you need some support, please seek some help - are your family open to supporting you?

Oh I see! You’re a child playing the copying game! How bizarre. Unhinged some might say