Nothing wrong with day trading. If he's profitable, great.
Long term holdings, never in mutual funds with the other assets available with lower fees. One problem with this is long term holdings that have large gains would trigger a taxable event in a non retirement account. Inside a retirement account, no problem selling and reallocating. Regular taxable account, have to factor in all the elements.
My neighbor asked me to help her with her CA PERS selections. Funny that virtually every single fund they had available, all trailed the index they benchmarked... the management fee.