The only reason why they would be doing that, is if they are somehow losing money because of that... Most banks flag accounts with deposits and withdrawals at a certain limit
and then it needs to be investigated for money laundering. If he has 1000's of transactions being flagged and they need to investigate, it would be a administrative nightmare. The
other possible reason might be that his money movement prohibit them from re-investing it... it's not in the bank long enough for them to make money on it. {They need longer
fixed deposits, to make proper investments}
