Estate Assets and Debts: If I Was Given Money Prior to Death

Hi sorry I am new here and i been researching for a couple of days between breaks and didnt find anything on what I need help with. This is also my first time using a forum so I am sorry if my question is already answered. So a few years back my dad was in the talks of opening up a religious prayer hall in another country, upon receiving this information my grandfather gave a huge lump some of cash to my mother to put toward the same prayer hall, my mother respectfully declined stating it will take awhile for everything to start and he should hold on to he money in the mean time. All in the while my dad opened up a new bank account under his name, my mom, and my sister so that if anything happens we open up that prayer hall with the money in that account. My grandfather also offered my dad to be the trusty to his estate but my dad declined saying he should have his son as the trusty so there would be no hard feelings so my grandfather placed his bestfriend as the trusty and my uncle as the second just in case his bestfriend passes as well Now it is not clear to me whether my parents eventually accepted the money and put it on that account (not an off shore account and completely legal). About 5 years later my grandfather passed away and my uncle convinced my mom and the rest of his brothers and sister so place him as the trusty rather than my grandfathers friend saying things like "we dont know him that well, we cant trust him" so everyone signed by making my uncle the trusty. Everything was going smooth from till my uncle realized my grandfather didnt leave cash behind for months before his passing he sent money out around the world to provide shelter for the poor, and the only asset left was jewelry and a duplex in the middle of LA. at this point my uncle catches wind about the money that was offered to my mom and keeps asking for a receipt and saying hes going to put my mom thru investigation and sue... my mom keeps telling him she doesnt have the money nor a receipt but my uncle keeps emailing her daily trying to turn the other brothers and sister against my mom saying basically saying my mom is a thief, now I dont know whether the money was received or not but I know it was offered in cold hard cash also if it was accepted it would have been throu my dad over 5 years ago for my dad and grandfather talked alot it in private and my grandfather saw my dad as his own son more than his own kids. My uncle now emails mom daily and talks to my mom on the phone in a very rude manner constantly making my mom cry, she told him a thousand times she doesnt have it and my dad doesnt want to get involved because he swore to my grandfather to keep everything they said in private. What can we do to stop the harassment and if the money was received can my uncle do anything about it? as far as the prayer hall my dad plans on building it after his retirement under my grandfathers name, and my uncle wants the cash or the receipt for taxes or whatever

Im sorry if this was really long but i didnt want to leave details out, please help me cause I am at a point where I feel like going off on my uncle but my mom and dad is wanting me to not say anything cause they know it would escalate very quickly with my anger

Estate Assets and Debts: If I Was Given Money Prior to Death