I have this funny feeling that Mbugua might be in for a surprise. Wambui might have left him only a small percentage of the property. The rest? Church maybe? Charity? Kids? Okay, the 'kids' might not get much. Mbugua was there for her more than the 'kids' were. I can't even imagine the kind of things he had to do for her especially in the last days.
But then again Wambui might have appreciated Mbugua being there for her when she needed someone most. It might have been obvious to everyone including Wambui herself that Mbugua got into this for money but I think he has earned it. He should keep the money and property, re-marry and get kids of his own like 'everyone' else.
Having said that, I don't care how broke/poor a man is, he should never marry for money. Women should also not marry for money but let me not even go there. That war was lost ages ago.
Never count on making a good sale. Have the purchase price be so attractive that even a mediocre sale gives good returns.