Hello. My name is XXXXX XXXXX I will be happy to answer your question.
I am sorry to hear about your brother's difficult situation.
Most courts have held that an engagement ring is a conditional gift which becomes an actual gift when the set condition is met, i.e. marriage
If your brother's fiancee had broken off the engagement, then your brother can sue his fiancee for the return of the engagement ring or in alternative for the value of the ring.
Your brother would have to sue his fiancee in the court that is local to the fiancee's residence in Massachusetts and the maximum amount that your brother can sue his former fiancee for in the small claims court is $7,000 and if he wants to sue for more money, then he would have to sue in a different court and hire a local attorney, which can be cost prohibitive.
Below is the link to the official Mass. website that explains the small claims process and related court costs:
I wish you and your brother the best of luck!