Trip to visit my son

I am an American born citizen. 40 years ago while living in the UK I gave birth to my son Adam. In 1979 I brought Adam home to the US to escape an abusive marriage, he was 3. I contacted immigration and was told Adam had citizenship through me. 36 years later my son is contacted by his biological fathers family saying the dad wanted to meet Adam. There had been no contact since 1979. Adam applied for a US passport and was told he was not a citizen. We contacted immigration and have filed all the paper work and paid the fees. We asked at the time if it would be possible for Adam to get a UK passport and make the trip to meet his dad. He was told he could. On trying to return home he was told his ESTA had been revoked and wasn't allowed to board. We are still fighting to get him home. It has been 11 months and we are being told it could take up to 10 years for his return. Adam has been with me through my journey with Stage 3 breast cancer. I miss him and his support. I am so afraid I will never see him again. I am asking for help in getting air fare to visit my son . He is alone in a country  he does not know and has once again been abandoned by his so called father. I would be grateful for any help getting enough funds to make the trip to the UK. Thank you so much.
Also, if you would please go to Change.org Bring Adam home and sign my petition I would be so grateful.