Jemma went to Mexico twice, both times paid for by GoFundMe campaigns. She raised at least half a million pounds through various fundraisers (not only GFM) and there was a lot of dishonesty about the financial side of things (there are a number of threads on her that go into detail!). There was also a LOT of family drama and her own mother didn't go to her funeral. Sadly, she had three small children, so as much as she was problematic in lots of ways, I'm still sorry that she died. Her husband has now taken over her social media accounts and is continuing to fundraise 'for her babies'.
Edited to add: Jemma was featured on an episode of Stacy Dooley's sleepover show – you can watch it
here. It shows some of the same alternative treatments that Kate does, like the coffee enemas. Jemma managed to get a local company to build her a free 'healing house' in her garden that she used for the treatments (although it also ended up being used for her car sales business!).