If this guy knows what the MC's bank account is like, in terms of not just his financial power, but how frequent and large the contributions to the account are, he'd be wary of going against them -- not just because he'd likely lose them as a client, which would be a massive deal to lose a big fish client, but because clients of such financial means can obviously hire great lawyers and absolutely screw you over back, even with their account for your bank freezing their assets.
All that said, I'm kind of hoping the father is just being misunderstood, and coming on too strong, in an attempt to just help his son. He seems to be legitimately encouraging his son, and pushing him forward in pursuing his goals, despite not really getting it, so it would be cool if he just properly asked MC to help his son rather than trying to strong-arm the MC.