How is Uber a creditor of Levandowski's? Also, the crux of their arguments is that Levandowski violated the IRS's 'arms length' rule by investing the IRA cash

How is Uber a creditor of Levandowski's? Also, the crux of their arguments is that Levandowski violated the IRS's 'arms length' rule by investing the IRA cash in his own company which later sold for a fabulous profit on the shares he purchased (for pennies per share). I wonder how this would apply to the average software employee who can also, in principle, invest in their own (public) company via their IRA, or, perhaps, purchase shares in their (not yet public) startup via exercise of options (is this even feasible for most people)?