I wouldn't interpret his search for a rock band leading worship as something that negates the role of the assembly.
Organists seem just as likely to alienate song when performance is primary over prayer.
Hopefully, Bob, you'll find good jamming musicians who are aware of the assembly's role and contribute to prayer and spirituality through their talent. It happens in a lot of parishes. On another note, I wouldn't worry too much about specific wording of the communion songs. Most eucharistic prayers, even after the institution narrative, contain language that would be suspect if every text had to explicitly reference the Body and Blood of Christ. Communion antiphons in the missal occasionally make oblique biblical references to bread, wine, and cup.