Venerable Mettānando's interpretation of the Garudhamma is at odds with that of Ajahn Thanissaro. There is nothing there about bhikkhunis not being allowed to teach the Dhamma to bhikkhus.
7) "A bhikkhu must not in any way be insulted or reviled by a bhikkhunī...
8) "From this day forward, the admonition of a bhikkhu by a bhikkhunī is forbidden, but the admonition of a bhikkhunī by a bhikkhu is not forbidden. This rule, too, is to be honored, respected, revered, venerated, never to be transgressed as long as she lives.
The Pali for admonition is vacanapatha 4. bringing up (for trial), charging M i.251 (vacanapatha).
The meaning is to accuse of an offence. If a bhikkhuni sees, hears, or suspects a bhikkhu of committing an offence she should report it to the Sangha and they will then investigate the matter.