In Italy, your sister's situation is regulated by Article 46 of l.(NNN) NNN-NNNN which rules upon any international private situation, included inheritance matters.
As for the assets which are situated in Italy, this disposition unfortunately states that successions are regulated by the law of the State of which the testator is a national. As a consequence, if Maurizio was only Italian, his inheritance would be ruled under Italian law.
Under Italian law, your sister would have the right to inherit 50% of Maurizio's assets. To start the procedure, if anybody has not done it yet, you should first transcribe his death in the civil register of the commune (Comune) where Maurizio has last resided in Italy or at the closest Italian Consulate.
Under Article 65 of the same law, the foreigner decisions which state upon separation and divorce have direct effect in Italy without any further need to be recognized by the Italian judiciary. It means that a divorce decision taken in Yemen is fully legal in Italy.
It is true though that you need to transcribe the decision in the civil register where the marriage with your first husband is registered (it is called "procedura di annotazione del divorzio nei registri dello stato civile"). You can do it at any time and you need to present the following documents:
- the transcript of the decision of divorce;
- an official translation of the same.
The transcription has not a constitutive effect but a merely certifing effect (Quote Opinion of Consiglio di Stato n. 621 1/02/2008).
After doing this, you can transcribe your marriage with Maurizio, even post mortem.
This is the law. Nonetheless, the practice migh be much less clear and I would suggest you to insist to find another lawyer in Italy who can take care of your case. There are many steps to go through and the administration does not intepret the law always in the correct way, but I am confident that your sister might finally be recognized her rights.
This is a very well known international law firm which headquarter is in Italy and which specilizes on the subject and you might want to consult:
I hope this helps. If you are happy with my legal opinion, I would be very much grateful if you could rate it positively so that I can get compensated for my time without any extra charge for you as only the amount you have already deposited would be used.
I remain at your complete disposal should you need any further information.