An inheritance cashier's check - especially for such a large amount of money - would never be made out to "Cash" so that just anyone could cash it. It would have the beneficiary's name typed on the check after "Pay to the order of" to prevent anyone else cashing it. It would also have the bank logo with the bank name on it, which the check also did not have.
The last name of Jessica's deceased mother, aunt, and uncle was the same - Freeman - which isn't possible with Jessica's mother being the sister of her aunt, as she told Curt. Jessica's mother Betty wouldn't have the same last name as her sister's husband. All three of them cannot possibly have the same last name.