Is it just me or does what Dick Miles has written about chords above not make a lot of sense?

In his first posting he says Adorian[a minor [or modal]f major to g major,seems a common progression. (I thought at first that he might be talking about a tune that modulates, but apparently not).

Greg then challenges him, correctly in my view, by pointing out that "there is no F natural in the A Dorian mode."

Dick then comes back with just before you change to g,depending on the melody.sometimes this chord works face[a cross between a minor and f]and sometimes a brief d modal 7 dac can work when the melody is either a or c.

Now, it could be that this is way over my head, but it seems to me that we are still waiting to find out how F natural fits into this scale.

Can anybody help me?