I think you misunderstand - they're saying that the doctors would elect to receive less treatments than the average patient if they themselves were sick - presumably because they are well aware of the low likelihood of success and the brutality of going through it.

I'm not a physician, either, but this rings true with experiences from my own life, were people I knew who were doctors decided early to stop treatment and let the disease run its course (and subsequently passed away).

The person you are replying to is saying that doctors often choose to forgo treatment options that their patients undergo.

See https://hms.harvard.edu/news/how-doctors-die - "Physicians are less likely than the general population to undergo intense end-of-life treatments"