The Virtual Robbery

Imagine a scenario where a skilled hacker breaks into a wealthy businessman's virtual bank account and transfers ₹10 lakhs to an offshore account. The businessman, however, is unaware of the theft until 6 months later when he reviews his account statements. The hacker, who was hired by the businessman's estranged son to exact revenge, claims that the transfer was an "error of the mind" – a mental illness defence. The businessman files an FIR under CrPC, 420 (cheating) and the hacker faces trial in a BNSS (Bhutanese National Security Strategy) court. What would the legal outcome be? Would the hacker's mental illness defence hold up in court?