Surrogacy for my sister

Hi there I am interested in becoming a surrogate for my sister and her husband as they've already had a failed IVF attempt. Recently hes been diagnosed as terminally ill with tumours on his spine. We aren't sure how much time we have but they want to use her egg and his sperm to be implanted into me. Wondering if anyone knows if we can go through our GP and roughly what essential costs will. We are fundraising on FB at the moment and have set amount at 6000. TIA