For music activities that families can do at home, I highly suggest singing, dancing, and playing any music-related games that families already know! These could be hand-clapping games; jump rope songs and rhymes (no jump rope necessary); other game songs and rhymes; lullabies; songs, stories, dances, and games from their own culture or everyday life; and so much more! Song stories, song books, and storytelling are great also. These songs, dances, stories, and games are VITAL parts of a child’s physical and cognitive development and language acquisition.
Students can experiment with making their own instruments, or using "found objects" around the house (like in Stomp) to make music at home as well.
Sixth grade students, especially those in Band and Orchestra, could check out SmartMusic. SmartMusic is already used in middle and high schools throughout the district, and they are offering free student accounts until June. https://www.smartmusic.com
GoNoodle. It's definitely not music-specific, but has many gems in there. I posted a list with links to many of our favorites on my website.
There are so many good music websites and activities out there, however again, I'm not sure if there'll be limits to what I can officially share. But I'll post many things on my Google Site. I'll be uploading some music activity worksheets to my website soon as well.