Your character is going to die, and they know it. In 24 hours, exactly. There is nothing they or anyone else can do to change this.
1. Comment with your character going about their business on the last day of their life. They could be splurging on ice cream, they could be going to a rock concert, they could be marching up to someone's house to go 'sex now plz'.
2. Other, more fortunate characters can reply, helping the soon-to-be-deceased enjoy their last day. Or making it worse. Whichever.