Lyna looks more like a big sis in this update, not only her look but also attitude, is she really the big sis?
I through the story will be slow burn but instead it is fucking fast like riding a rocket! Are you trying to fast forward the story in order to make the sibling have sex with in three days before their mother arriving?
How you describe lyna's action in this update is a bit too much. In my view she is more like a pervert who trying to sexual assault her brother rather than trying to use teasing to get close to him(beach scene and bedroom scene), which make her less attractive but more disgust...
Moreover, when will mc be more alpha? If he keeps becoming beta then how can he protects himself from his pervert sister? He needs to be strong, strike back and fuck her brain out!
Btw, looking forward to see lyna wear that see through pajama(or is it an erotic clothing?) in front of her brother, I wonder who will surrender to the lust and make the move first. After all there will be no chances for them to easily fuck each other over in the house when their mother arrived~