Welcome to the site. Sorry that you had to find us all here and I am sorry to hear about your sister in law. But I'm glad that you've joined us here as you are in the right place for support and help and I know you'll get a load of both from everyone here. I too am in the UK, in Dundee, and my dad was treated here at Ninewells in Dundee.
No wonder the last 6 weeks have been a whirlwind for you and I know that your head will be spinning still with having to take everything in that is happening right now. I know that after my dads diagnosis it took a while for everything to sink in, but you are so doing the right thing in coming here and seeking further information. The more info you have and learn the better informed you will all be when it comes to decision making, and I know that your sister in law will so appreciate what you are doing for her.
As to ascites, they are quite common with the cancer and here is a link that contains more info on them -
http://www.macmillan.org.uk/Cancerinfor … cites.aspx
Yes as the others have said the ascites can be drained and this will help your sister in law feel much better, but they will need to be drained again and again as the fluid will keep coming back. And we were told by my dads Mac nurse that the fluid can come back quicker if it is drained off. My dad had ascites but he never got it drained.
Have you heard of AMMF? It is the UK's only CC charity and you will find a ton of info there that is purely focused on CC and everything to do with treatment centres etc in the UK. Here's a link for you -
http://www.ammf.org.uk/cholangiocarcino … options-2/
I know that you'll find a ton of UK related there.
Has your sister in law sought or thought about seeking a further opinion on everything? She is entitled to do that under the NHS and her GP should be able to refer her to a centre or oncologist of her choice.
As to a strict diet along with hemp oil during chemo, I have no thoughts or knowledge on that at specifically. But I would stress that going down a certain road without taking medical advice on that would not be advisable IMO. The Gem/Cis combo that your sister in law is on is a very common combo for this cancer and there are a ton of posts here on the site about it.
I hope that you will keep coming back here and let us know how everything goes. We are here for you and will do our best to help in any way if we can. Ask any questions that you have and we'll answer as best we can.
My best wishes to you and your sister in law,