Hugo Donaldson's condition is a rare and aggressive childhood cancer. Photo / SuppliedHugo Donaldson’s condition is a rare and aggressive childhood cancer. Photo / Supplied

Hugo Donaldson is one of only eight patients accepted worldwide so far for a CAR T-cell clinical trial at Texas Children’s Hospital in Houston, his father describing the treatment as possibly the last hope. Photo / SuppliedHugo Donaldson is one of only eight patients accepted worldwide so far for a CAR T-cell clinical trial at Texas Children’s Hospital in Houston, his father describing the treatment as possibly the last hope. Photo / Supplied

What is the therapy?

Hugo Donaldson's family are facing a $500,000 bill to make the trip to Houston in the hope of successfully treating his Stage 4 Alveolar Rhabdomyosarcoma. Photo / SuppliedHugo Donaldson’s family are facing a $500,000 bill to make the trip to Houston in the hope of successfully treating his Stage 4 Alveolar Rhabdomyosarcoma. Photo / Supplied

‘He knows it’s serious’