In my view the link above makes some sensible points.

However, there are many points in it which I disagree with and/or are not supported by evidence.

Some examples:

"Cancer feeds on mucus."
I know of no evidence to support this claim.

"Cancer cells thrive in an acid environment."
I know of no evidence to support this claim. Body pH is controlled, through well-understood physiology, within narrow limits. Food intake has a negligible effect on this.

"Cancer cell walls have a tough protein covering."
This is factually incorrect.

"Cancer cells cannot thrive in an oxygenated environment."
This is factually incorrect. Cancer cells, like all body cells, need oxygen. Sometimes solid tumours do not grow quickly because they have an inadequate oxygen supply. They often respond to this by producing growth factors which lead to increased blood supply, as a source of the oxygen which they need. Trying to work out how to prevent this is the basis of development of some novel chemotherapeutic drugs.