Okay need help with my story WRITERS ONLY?

Okay so in my story my main c is singing her brother to sleep so he wont have to worry about this big fight scene next. i'm pretty sure some of you know the song hush my babe if not its this lovly lullaby my parents used to sing for me when i was little and i wanted to let her sing it but i'm scared to use the song.... what are your thoughts should i use it? im not that good with writing songs