My grandfather was conned into signing over the deed of his property leaving him with only a life estate by people unrelated to our family

My grandfather was conned into signing over the deed of his property leaving him with only a life estate by people unrelated to our family. The SSA, Department of Aging, police, etc were involved. However at the time he was threatened into not pursuing charges by these con artists. Now that they're(the con artists) are gone by a Peace Order I helped him with, he wants to press charges and try to get his property back. The police have an open investigation into violating their(con artists) fiduciary responsibilities(as they were also on his bank account), however they've been no help and it's been well over a year. I've considered committing title fraud, however I don't want to go to prison. I've looked into possibly having a voidable deed, quiet title action, quit claim deed, grant deed, beneficial interest, and a new will we currently have. I'm curious if there's anything else we can do to get his property back into his name? This is time sensitive as he is currently 87 years old. Also, his previous attorney we believe to be in on it as he mentioned it he has to testify, he will tell the courts my grandfather willfully signed it over, my grandfather is still of sound mind. One last thing, I have proof they've done this to another old man and now they own over 200 acres of land as well as my grandfather's property and a home they purchased by taking a loan out on my grandfather's property.