How to access family site from Android

Not sure what you mean by "family site" or what you want to do exactly. Android devices have very limited and strictly controlled access to Apple's features so it would help to know exactly what you wish to do.

An Android user can get access to the features of iCloud through the https://icloud.com website.

From the family sharing site

• Family Sharing requires a personal Apple Account signed in to iCloud. Music, movies, TV shows, and books can be downloaded on up to 10 devices per account, five of which can be computers. iOS 8 or later and OS X Yosemite or later are required to set up or join a Family Sharing group and are recommended for full functionality. Not all content is eligible for Family Sharing. Content can be hidden by family members; hidden content is not available for download. Content downloaded from family members or acquired via redemption codes is not subject to Ask to Buy.