My Mil passed away and it's worse...

I need to tell someone, someone who's not connected to the situation to offer some insight into this situation. I apologize beforehand if I ramble, sound petty or angry and this may be long one. I also want to be clear that this is just my side of this story and that the other folks involved have their own.... I will begin by saying my relationship with my mother in law over the past 14 years has been complicated, unpredictable and frusterating but I loved her. She dealt with mental illness that made it difficult to always express that love but these last few years have been more easy because I grew up and learned how to manage that relationship but this story isn't about my relationship with her, it's about my husband, her only child. Their relationship wasn't easy either, it was complicated and hard but they loved each other very much. My husband's father had passed away some time ago but he never knew him so his mother was his only blood relative he knew until he and I had our children together. His mother remarried when my husband was 12 years old and his step father became a sort of friend to him when his mom's mental illness would read it's ugly head. His stepfather and him would commiserate and help each other through those times, those times got closer and closer together as time went on and eventually her mental illness was ever present. Fast forward to February of this year and my husband's mother is court ordered to a nursing home because she frequents the e.r. too much and she and his stepfather couldn't care for her at home properly. She begins telling the doctor's, the nurses, me and my husband, anyone who would listen that her own husband had been physically, and verbally abusing her, that he had her committed, that he was having an affair. We didn't know what to believe at the time, she wasn't thinking clearly and at times didn't make sense. His step father, of course denied all of the accusations and we believed him. As of today, I don't know if DHS has investigated. She was eventually moved to a nursing facility with the promise of coming home after a mandatory 30 days there as long as there was some kind of in home nursing to care for her when came back home. So her husband decided to call a previous neighbor they had years ago, and see if she would come live with them and them take care of her. I'll refer to her by the name Nikki. We had never heard of Nikki before, never seen her, never heard name mentioned before this moment but she agreed to come care my MiL without any medical expierence but she was getting room, board and money to do this. My MiL told she suspected something going between her husband and Nikki but I didn't think much of it , there was a 40 something year age difference overseen them and it just seemed highly unlikey all the way around. My Mil also expressed on NUMEROUS occasions that she her husband to be removed from being the executor of her will and the power attorney because he was trying to take her ouse away, the one her mother paid for and then gave to her in the event of her death. The stepfather swore he wasn't going to take the house, that he didn't want it. My husband was starting to grow more suspicious about his step father, he wasn't sharing medical information with him or the information he was sharing was contradicting and didn't make sense. By that time Nikki arrived in town having lived in California for tale past few years. Nikki arrived on March 10th and my Mil passed away March 12th,after being stable and recovering for weeks, she was 10 days shy of being able to return home. My husband and our children were shattered, completely devasted. That day we just grieved and helped our children grieve, it was overwhelming for them. The next day, everything began to unravel further. My FiL called my husband and told him to come pick up the death certificate and to see her hand written will the next day. His stepfather brought Nikki with him to the funeral home, took her with him to have her cremated, took her with him to listen to her favorite music at favorite spot, took her with him to submit her obituary that he had her named as one of our family. He didn't and wouldn't included my husband in any of this, he hadn't even talked to or asked about his grandchildren. It seemed...odd. Then my husband asked how long Nikki would he staying...and that's when the weird turned crazy. His stepfather became angry and defensive , told him it was none of his business. My husband that morning had messaged Nikki directly( I'll include a screenshot at the end) asking her how she knew his mom and her reaction was much of the same...defensive. My husband and I thought it would be best if I was the one who went over there to get the obituary and death certificate to avoid any confrontations, no such luck. Nikki answered his mother's door in her PJ's, and then his step father starting yelling about my husband. How he wanted nothing to do with him or us and what he did now was none of our business and he get restraining order on us if we tried to contact him any further. Now I'm not normally a dainty little thing but this was two days after my Mil died and my 11 year old son was waiting in the car for me so all I really had to offer were a lot of tears and a lot questions. I left that house by him scooting my towards my car, threatening with police if didn't get off the property now and more questions than I had come there with. For my husband it was pain and betrayal on top overwhelming grief, I had never seen him so hurt and angry in our 14 years together. My husband and his stepfather got into one more screaming match before another threat of a restraint order was given. Nikki had also logged into my MiL Facebook account and was posting and going through her message before blocking my husband and I from her Facebook page. 22 days after my husband's mother passed away, Nikki announced on Facebook that she was in a relationship with my FiL and she was living with him. They have not contacted my husband or our children, they won't allow my husband to have his childhood pictures with his mother. To say this has completely and utterly devasted my husband and kids would be an understatement, we are struggling to move forward. Sorry this was so insanely long, there are still so many details I had leave out. I just had to put this somewhere, so if you read the novel, thank you.