I don't think Bob said anyone is a failure. I read it as meaning , trying to convince him, you would fail .
Whilst. I think, there is no doubt that you are correct and honorable in your desire to provide as well as you can , for your loved ones. There are certain problems, not connected with finance, or security of investment, to consider, especially if you are proposing to build such a palatial home in the relatively poor region of Issan. The reason why most expensive houses are built on projects is because of security. Normally a security company is employed to patrol the entire area . There is also the "Herd" effect. With many properties to choose from, we hope the robber won't choose mine . If you build an individual property you won't have this, so you must consider what alternatives to protect your investment you must put in place .
You have also to worry about those good old human emotions, jealousy and envy . You will get a lot I assure you, not all from the Thais.

In my mind the best you can do for your family is to help them blend into the community, not stand out from it .