They say "A little knowledge is dangerous". This strikes me as one of those scenarios. Your experienced friend is at a place in his (or her) dancing where he sees Bronze Foxtrot as nothing more than a stepping stone to Silver, as though Silver were the ultimate goal above all else. And if that were really true, what indeed would be the point to Bronze Foxtrot?
Of course, with even more experience, your friend might start to see Bronze Foxtrot in a number of different ways. It can be thought of as an entirely separate dance, useful for specific situations and or styles of Foxtrot music, much in the same way you might choose EC over WC Swing (or vice versa) depending on the situation.
It can also be thought of as something to blend together with your Silver Foxtrot, since there's no law that says once you start passing your feet, you're never allowed to close them. I myself like to mix it up quite a bit. Actually, it's a pretty good measure of your leading and/or following skills to mix weight changing figures together with foot passing figures.
Whether I'm dancing socially or choreographing for a show, I don't like to be bound by the contrived notion that one has to either close or pass, or stick to any specific rhythm based on their "level". Part of Foxtrot's charm is its versatitlty both rhythmically and stylistically. As long as what you're doing looks and feels right to you, your partner, and (in the case of a show dance) anybody watching, then it's fair game.
Oh, and Silver isn't limited to SQQ figures. Continuity Basic, Grapevines, Standing Spins, Pivots, Chasses, Syncopated UAT's, Weave actions, Continuity Hesitations, and others are all perfectly valid examples of Silver-level figures with non-conforming rhythm.
Regards,
Jonathan