I only read some things in a forum for spoilers, but apparently, Andrea is alive, but he is truly sick. He is the one responsible for turning back time and is also the reason why Lily is severely sick right now (in their previous life, Lily did not awaken, but because Andrea turned back time, it triggered her ability to awaken and is experiencing the fevers the people from Trovancha gets right before they get an ability).
He definitely loves his sisters and also cares for Lily deeply but if I remember correctly, he is keeping himself away because he didn't want his sisters to suffer from seeing him so weak (y'all can correct me on this part, I don't really remember why but this is just my hunch.)
Also, Andrea wasn't sick before, he just became like that because that is the consequence of him turning back time.
He will come back in some part later in the story and he'll make up with his sisters.
Novel readers or anyone who knows, can you please spoil me on Andreas (?) the mc's older brother. Like where is he? What happened to him? more importantly, is he alive?