Cat Janice, the musician mom who went viral for dedicating her last song to her young son, has died of sarcoma cancer at 31.Her family announced the news on Instagram, saying that she died peacefully Wednesday morning in her childhood home and that her brother will continue to manage her brand — including more art that she had wanted to release.“We are eternally thankful for the outpouring of love that Catherine and our family have received over the past few months,” the statement read. “Cat saw her music go places she never expected and rests in the peace of knowing that she will…