A sister asks if a Muslim convert can inherit from a non-Muslim. She has no Muslim relatives and her mother has put her in her will?
This is a big misunderstanding in Islamic law from Muslims. The misunderstanding comes from an authentic hadith in sahih Bukhari that the Muslim doesn’t inherit from the disbeliever and the disbeliever doesn’t inherit from the Muslim.
We have to ask ourselves what does inherit mean though? When it comes to inheritance we can divide the money into two categories. When a person dies there is a portion of their inheritance that is dictated by Allah. So for example, according to the rules of the Quran 1/8 goes to the wife and so on. If a person dies without a will in a Muslim land, there is no need for it because the money gets divided in accordance to the Quran.
There is a third of the wealth that is not mentioned by Allah and we can give this third to anyone we choose to, whether it is a Muslim or non-Muslim. You may write in your will about this third to this person.
If you do not live in a Muslim land you are allowed to increase the one third share and leave it to your non-Muslim relatives if you do not have any Muslim relatives. This is a fatwa by several Islamic councils in the West. If you have Muslim members in your family, you have to stick to the laws Allah has set and give them their share.
Bottom line, you may take what a non-Muslim relative has left for you because she is not bound by Shariah. And if you have no Muslim relatives, the shares that Allah has assigned are not based on non-Muslims, so you can stipulate in your will who the money goes too.