I’d think very carefully before going abroad for treatment, especially given your friends medical history, as these medications could affect treatment. If any teeth can be saved, please consider this option very carefully. Ideally, get a full treatment plan from a dentist in Australia, even if you do decide to go abroad for treatment. You will have a better idea of what is required and the time needed to restore your friend’s dental health. If they do decide to have all their teeth out, then there are implant treatments to restore complete arches of teeth, where the implants are placed towards the front of the mouth which can be useful if there has been bone shrinkage.