Some treatments may eventually turn out to affect some cancers by improving immune function, but in general, claims of multi-disease efficacy are almost certainly bogus. Simplistic sounding, unconventional theories of AIDS, medicine or biology are often given to explain why the same treatments will work for radically different diseases. Anybody claiming an HIV cure but whose area of specialization is far removed from AIDS, is suspect. The average cardiologist or general practitioner didn't learn about AIDS in medical school, let alone people without medical degrees. Practitioners without previous achievements in the field of medicine are extremely unlikely to unravel the complexities of HIV disease.
Any practitioner keeping secrets about the treatment being offered is highly suspect.
Anybody offering a treatment that requires travel to foreign countries is suspect. Normally, the reason to do something that isn't allowed here. Legitimate studies in other countries are usually filled by local people, and are free, as trials must to be. Promising treatments approved overseas can often be imported for personal use. Anybody who cites articles in obscure publications or research done in obscure institutions is suspect.