Spouse failed her duties as executor of her deceased spouse's will, remarried and died. Does new husband have claim on undistributed estate?

My brother was married and died 2 years ago. My sister-in-law claim to have marry a foreigner a month ago, who also has been in the country for the same time period. She died shortly after. Right now, there hasn't been a funeral. In addition, this foreigner is going through her property like its his stuff. He has put locks on the property and is trying to cash $100,000 checks, accessing cash on property, and is looking through documents which he should not be doing. We are aware that my sister-in-law was hiding assets after my brother's death and tried to hide his will. We would like personal affects like family photos, videos, writings, etc. of my brother back. Does a will override this assumption ownership after? And is there a way to lock down the movement of assets until legal matters are settled?