Possible Clues:

• Open air church music
• Frank's on key, singing unaccompanied
• Indulging in sport? Yen disappears when boy's into that church music
• Unaccompanied liturgical chant
• Ordinary boy with good example of Gregorian chant
• Simple melody from piano is a long new arrangement
• It's not complicated to one of the family members with key to church music
• Unattractive boy with grand church music
• It's clear one of the family members finished singing church music
• Chant a simple ditty