Getting Repayment For Unpaid Promissory Note

Hello all, throwaway for obvious reasons.

My widowed mother, (70F), lives in an upscale area in CT, in a community of other older individuals of similar or extravagantly greater financial means. It’s a tight knit community, and a few years ago, she befriended a couple who own one of the most impressive properties in the area; a big beautiful house with almost an acre of land, directly on the beach. Additionally, they own upscale properties in several other states, and the husband is President and CEO of an independent oil and gas producer/operator with interests (and presumably properties) both domestic and international.

Due to their closeness and their perceived financial means, my mother was happy to grant them a promissory note for over $75k when they asked, to be paid 3 months after the signing of the note. That was over 2 years ago. In that time, they have continually gave my mom the runaround; saying that money wires were scheduled that never came through, that money was supposed to be hitting accounts that never did, etc. We have also found out that not only has their beach house been foreclosed upon, but they’ve both attempted and succeeded in “scamming” other widows in the area out of money as well, one of whom just gave them $40k in sept 2023. They also have a number of lawsuits that have been filed against them for similar shady practices.

They did make a one time repayment of $25k, but outside of that, nothing has come in. And over the time the promissory note has been outstanding, they’ve continued to take trips with their families, have parties at their house, complete expensive landscaping projects, eat out at expensive dinners, buy gifts for people, spoil their grandkids, etc.

My question is, what, if any, legal recourses do we have to force them to repay the promissory note? Or what kind of pressure can we apply to them to make their life less comfortable until they pay? What kind of dos and donts should we adhere to when dealing with them? Have already spoken to one litigator, but have been thinking of reaching out to forensic accountants, collections agencies and other legal experts to really light a fire under their asses and move things along. Thanks so much in advance for your help!