Legal Question in Business Law in Oregon

It appears that your step son's father is employing your step son as an employee. That arrangement creates certain obligations and responsibilities between the two of them as employer and employee. You are not part of that relationship and so you do not share in those mutual obligations in any way. You are at liberty to gift any funds you want to your step son. Unless you are part of the business that your step son's father is running, or have access to the administrative functions of that business, then by paying your step son you have not discharged any obligation his step dad has as his employer. Based on the information that you have provided, you have not violated a legal obligation that you might have in this scenario.