The rulings resulting from prohibition through breastfeeding

Question:
Our brother asks his final question: What are the limits of interaction with male and female siblings through breastfeeding? For example, is it permissible for a brother through breastfeeding to travel with his sister through breastfeeding, or to stay with her in the same house? Or to kiss her as he would kiss his sister by blood? Please clarify this, and what are the exceptions—what is not permissible to do with siblings through breastfeeding?

Answer:
Breastfeeding is like blood kinship, as the Prophet (peace and blessings be upon him) said: This means: regarding seclusion and the status of being a mahram. She is his sister just as his sister by blood is his sister. So there is no harm in being alone with her, no harm in traveling with her, no harm in shaking her hand, and no harm in kissing her. However, the kiss should be on a part other than the mouth. It is better for it to be on the head or the cheek, as al-Ṣiddiq used to kiss his daughter 'A'ishah on her cheek.
So the conclusion is that it is the same as blood kinship, but it is not the same as blood kinship in maintaining family ties. Kinship is specific to close relatives. This applies only to the status of being a mahram and seclusion, not to financial maintenance or maintaining family ties. This is based on his (peace and blessings be upon him) saying: May Allah send blessings upon Muhammad.

The presenter: O Allah, send blessings upon our master Muhammad.