Breaking into Mac laptop

[Burnadell]

My BIL's son died from Covid. He was single, worked from home for a tech company. He changed the password every month on his laptop. After his death, there have been some withdrawals from his bank accounts. My BIL needs to access the computer to locate any financial assets because his son did everything online...no paper statements, etc. He was told by someone (I don't know who) that a Mac laptop cannot be accessed without the password. Is this correct? Is there NO WAY to get into the Mac without the password even by techy wizards?