To think I can squeeze into a 5 person car with just 2 other people

@HerLivingontheHilltop my ds is on a world tour withthe RN. Heard from him lots. Facetime too.

If you maintain your car you don't need to carry all that extra oil and windscreen washer fluid- you top up before a journey and most cars now have an annual oil change with an annual service.

Her son is possibly going away with the Navy (my guess) for a year long tour. If so, not sure how much communication they are allowed and how easy it is, for security reasons.

I was accused of being a 'competitive underpacker' in another thread. Nope, just realistic packer. I refuse to belive people need this much stuff. Whenever we go anywhere as a family or friends, we carpool. With very little adjustments we have always managed to fit everyone and everything. The idea that someone would have to use hours and several train changes wouldn't even enter anyone's mind. 3 people going for a hike with Ford ka? Tight fit, but you make do. You do not make one person take an inconvenient train.

i don’t think you would realistically fit 5 people into a Ford Puma comfortably. They are not really that big. As for fitting 3 people in, that could work depending on how much luggage the other 2 are taking. Sounds to me like they just don’t want to travel with you. It’s a bit mean of them. Why don’t you call your son and explain that you feel unwell, it seems like a big journey to make. These days with FaceTime and Messenger you can still maintain good contact with your son. Hope you feel better soon.

Cumbersome to somone with neck and shoulder problems does not mean she's taking loads of luggage.

And entitled for asking for help from close family members when they're all going to the same place? Really?

For a weeks trip a suitcase each should suffice. Even two fairly large ones should fit in most normal sized boots. And you are going for three days so will probably only have a small bag that could sit beside you if it absolutely can’t go in the boot (which I don’t believe either!).
Some people have a lot of shit in their boots that seems to reside there permanently and doesn’t really have a place in the house. My aunties boot is a riot of blankets, bags for life, crates of soft drink that she buys in bulk and keeps there and other random crap. Could this apply to your sister?
are they taking big items like bikes, golf clubs that sort of thing?
Anyway I don’t think Yabu and they sound nasty.

Most of my boot is taken up by safety equipment, oil, washer fluid etc. That's before luggage; which I plan around how many people will be coming, how much luggage they'll have etc.

If someone asked last minute to get in the car it would be a no!

My parents are going to visit dd1 tomorrow on the south coast for a few days and they've managed to squeeze me in. I am not travelling light as I have a lot of stuff for dd and gd.
We used to have a Renault clio and we went to the Isle of Wight for a week - 5 of us, 3 adults, 2dc in car seats, a pushchair, nappies, a side for the bed (dd3 had just broken her collarbone falling out of bed). It was a bit crowded but we needed it to work and it did.

OP does your sister look after your father by doing housekeeping
Taking him to appts
Generally organising his life ?
If so maybe she feels she doesn't want the added burden of being responsible for another adult.
Esp if she feels all the looking after joint father is left to her ?

We go to Center Parcs in my Dacia Duster so similar car size and there are 3 adults, my DS8 in his high back booster, we have an electric cool box and all the coats and shoes in the boot, a roof box on with all the non refrigerated food and luggage and the bikes on the back. I would think u would be able to fit 3 adults and luggage in her car.

I take one pair of shoes (two at a push) and 1 jacket. Why do you need several jackets/coats?

There is clearly more to this as it is madness for the three of you to travel to the same place at the same time to do the same thing and not travel together irrespective of your health issues.

Of course the three of you could fit in a standard sized car together, if your sister wanted to take you she clearly could.

As an aside when myself & my husband go on holiday we get all our stuff for a week self catering plus a guitar & exercise gear in the (medium sized car) car with room for three people.

I dont really know what the definition is of masses of clothes, perhaps. I normally take around 5 or 6 pairs of shoes, quite a few jackets/coats. I have half a ruck sack of medication and my OH has medication boxes, thats not ideal but has to be taken. He takes around 4 or 5 pairs of shoes.

We cant fit a suitcase in the boot with the 'car box' there anyway, which holds a lot of emergency things in case of breakdown or fixings etc.

Anyway, my point is, and its not helped on the thread by OPs limited responses, there is a huge assumption on the thread that the other pair are simply being horrible, but perhaps they're just full to the brim. Perhaps they're very light packers and that that assumption is right. Perhaps they like to take the kitchen sink and so just cant fit anything else in. Has OP asked this question?

I find on many holiday threads theres a competitive edge of underpacking, look how little I can get away with

I got called stupid for saying pretty much this.

@Emma6cat is your ds in the navy? If so there may be a parents support chat or group on Facebook ? You could ask in there if anyone is going from the north.

I can't belive people here are saying that lugagge is an acceptable excuse for making a family memeber to take 3 changes with a train when they are going to the same 'event' in the same destination.

@Emma6cat
This does seem weird.
Does she know about your ailments?

Could you ask her one last time stating:
I am in a pretty bad way at the moment.
I will just be taking this bag (show her a photo) which can be in the back with me.
I will contribute to petrol

If I go away for the week, I always fill the boot of a car with stuff.

It would be good to know why she has declined, seems like a pretty easy 'ask' to me. Unless there's a huge backstory e.g. you've got form for bringing tonnes of stuff with you on previous occasions

Why the assumption it doesnt apply? Personally no a suitcase isnt enough, I cant fit it all in a suitcase. In any case we cant fit 2 suitcases in the boot, so the back seats go down

@soupyspoon Do you take masses of clothes with you? I take a medium suitcase for a week in the UK. I can fit in 3 pairs of trousers, several T shirts, a dress, 2 jumpers, nightwear, loads of undies, and then there's what I wear to travel in, which is another 'outfit'. I take a small holdall with toiletries and shoes etc go in a bag usually in the footwell or a corner of the boot.

Do you have a very small boot?

How much stuff do two adults need for a week away?

We used to go away for two or three weeks at a time in. Peugeot 308 with DS in his car seat in the back and enough stuff for two adults and a baby including the pushchair.

They're taking a trip to see her son off, they're driving past her house, and yet her sister is happy for her to shlep down on the train and her dad is too much of a wet fucking lettuce to get involved.

I genuinely cannot imagine treating someone I loved like that in preference to just, you know, packing a little lighter.

They sound awful. If not be making plans with them again unless they include you fully.

Why the assumption it doesnt apply? Personally no a suitcase isnt enough, I cant fit it all in a suitcase. In any case we cant fit 2 suitcases in the boot, so the back seats go down

Like others on the thread the lack of explanation means that we cant comment really.

Well we take what we use to be honest and even without any wetsuits (which are only because OH wont go paddling in the sea without it, we're not deep sea divers!) there wouldnt be room for anyone else. The bikes we dont take every time. Im just surprised people would have room.

We stay in a nice cottage too!

We go for day trips out, restaurants, cafes etc. We're not 'hobbyists' - we're just bog standard holiday makers.