Assalam o alaikum,
I apologise in advance for being blunt in this post but this issue is affecting me a lot and I need some guidance. Its been 6 month of my marriage and I am not happy with the way my husband (30yrs) and her younger sister (23yrs) behave. I read about sibling kissing eachother on multiple islamic websites and found out its okay to give peck on cheek to mehram. But is it okay for a 23yr old girl to kiss her brother on cheeks, neck, hands, legs (including touching his body frequently, and its a two way, my husband is equally involved) not just once in a while but daily multiple times in a day.
Initially I ignored it thinking maybe my family is strict and siblings may act this way depending on their upbringing and environment. But as days passing, I am realising my husband spend most of his time with her sister, not me (since corona lockdown) and whenever i pass by, I see them either kissing or cuddling each other.
Please do consider this question and guide me.
Their act is inappropriate, they must avoid this. In the Shari'ah, one can hug their Mahram, shake their hands, kiss but on the hands, in between the eyes or on the head.
قال الملا علي قاري "فأخذ بيدها فقبلها " أي بين عينيها أورأسهاوالأظهر الاول كما رواه ابن عدي والبيهقي ..........اه "وكان اذادخل عليها قامت اليه فأخذت بيده فقبلته" أي عضوا من أعضائه الشريفة والظاهر أنه اليد المنيفة
(مرقاة المفاتيح 8\469,كتاب الأدب,باب المصافحة والمعانقة,رشيديه)