No, I'm not going there. I don't care if he uses a drone to photograph his own business without a license. Not sure he would need one for that anyway.
How would he NOT need Part 107 for that? Anything that is NOT hobby/recreational requires a Part 107. An exchange of money is not the deciding factor but any way in the world someone is "doing something for a business" it is absolutely NOT, in any way, HOBBY/Recreational! That's pretty much a no brainer IMHO.
Related question here. People speak of "possible fines." I am studying for my 107 but do not have it yet. I am exclusively flying for fun. I am however getting nibbles like "if you get me some footage of this, I might be able to get you some money down the road." I have not done it and don't intend to. But what specific fines are we talking about?
Pilot Faces $1,100 per violation plus other penalties (civil, local ordinances etc) for "Acting as an Airman".
The person who hires him (aka person who causes the operation) is liable for up to $11,000.
A Realtor could face other issues such as "possible loss of REA privileges" because they are required to be ethical in everything they do. A REA who knowingly breaks a law can face penalties on state and national levels.