You know, at the time, David Thomson didn't even know that Oliver was his biological son.
That was because David's demands were very low — as long as she could always stay by his side, he would try hard to have another child. He didn't mind her possible "affair" with Francis Turner, although in the end, it proved that there was none. As for the little guy? He chose to selectively ignore.
In fact, it was lucky that he did so. Otherwise, Charlotte Rodriguez might have really run off with Francis Turner at the time. Now, David can guarantee that if Robert Thomson continues to be a hooligan in front of Thomas Smith, in the end, Emma Smith might still end up with him, just that their feelings for each other would be greatly diminished.