Chris Willman Senior Music Writer and Chief Music Critic When Bobbie Nelson, longtime pianist for her brother, Willie Nelson, died in March 2022 at age 91, she left behind a recently completed posthumous album, recorded collaboratively with singer Amanda Shires. That record, “Loving You,” is finally seeing the light of day and shedding additional daylight on Nelson’s supreme talent as a player, which wasn’t always the main point of focus in the Nelsons’ family band, for obvious reasons. As a happy byproduct, this beautiful labor of love also casting sunshine on Shires’ skills as a vocal interpreter, as they both take on Willie songs, standards (“Over the Rainbow” and “Summertime,” the latter with a guest vocal from Bobbie’s brother) and other shared favorites.