If a woman passed away without a Will and is survived by her live-in boyfriend of 15 years and 2 adult children, who is legally supposed to make decisions concerning her estate?
The children would make the decisions (and will also inherit under "intestate succession," or the rules for who inherits what when there is no will). "Boyfriend" is not a legally recognized relationship and gives him no inheritance rights and no legal authority. He would only have inheritance rights and/or authority over her estate if she had a will which left him part (or all of her estate) and/or named him as excutor.
Typically, an executor of a Will makes decisons for an estate. However, in the case where a peson dies without a Will, then a "personal represntative" fills that role. Accordingly, the mother's boyfriend could file for appontment as the PR. Typically, family members are appointed but close friends may also be as well. If this woman's children (or any one of them) wants appointment, then they should apply for it. The court will make the final determination as to just who becomes the PR. As for any inheritance rights, the boyfriend is out of luck since without a legally recognized relationship to the mother, (i.e. a spouse) he is not considered to be an "heir". The children will inherit under the laws of "intesate succession" since their mother had no Will.