I went to visit two women in Yarl's Wood on Sunday. Is that where your friend is? The women I spoke to said they found being in Yarl's Wood very lonely so I think the best thing you can do is go and visit your friend. Visitors are allowed in for 3 hours at a time which is not great but long enough to catch up and offer some emotional support to your friend at this very difficult time. I know that the detainees there (in Yarl's Wood) are only given 70p a day to live off and they have to buy their own toileteries (shower gel etc) out of that so if you do visit your friend you could take her some shampoo or something. Another thing that any detainee would be grateful to receive is top up for their phone - this is so important for them to maintain some contact with the outside world and as I said, they do not have much available money. I guess you will have to find out what network your friend is on first.
I hope this helps.