Here in French:
https://www.vermoegenszentrum.ch/con...-heritage.html
No will:
If she/he dies you get 75% of the estate, the sister 25%
If you die she will get 75% of the estate, your mother and father each 12.5 %.
Will:
If she/he dies she must give you at least 37.5%, if not you could sue if you wish to do so (only possible after the testator is dead). Sister can be fully disinherited.
If you dies you must give her/him at least 37.5%, and each parent 6.25%, if not they could sue if they wish to do so (only possible after the testator is dead).
Disinheritance of the father. See from Art. 477 Civil Code onward
https://www.admin.ch/opc/en/classifi...ndex.html#a477
"still owes my mother a large sum of money from not paying the court ordered child support." might be a valid reason for disinheritance.
If you have the default marriage property regime which is "Contribution to jointly acquired property"/"participation aux acquêts"/Errungenschaftsbeteiligung, the estate consists of the good of its own + half of the jointly acquired property.
https://www.ch.ch/en/matrimonial-regime/
Goods of its own are: what the partner had before marriage, all gifts, all inheritances, and all profits from the good of its own.