All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
The status of the parents is great and obeying them is obeying Allaah and pleasing them is pleasing Allaah. Allaah says (which means): {And your Lord has decreed that you worship none but Him. And that you be dutiful to your parents…}[Quran 17:23]. Moreover, the Prophet said: "The pleasure of Allaah is attained by pleasing parents, and the wrath of Allaah is ensued by angering parents." [At-Tirmithi] So you should endeavour to please the parents as much as possible.
Therefore, we advise you to try to convince them that it is better to build in an area that is less expensive. First, seek Allaah's Help in doing so, then seek the help of righteous and pious people who could influence him, and we believe that he will agree with you. So if this is achieved, then all perfect praise be to Allaah; however, if he insists on his view and you are well-off and there is no harm on you in fulfilling his request, then you are obliged to obey him. This is not being extravagant as long as you are financially able to do so. Being extravagant differs from one person to another because of the difference of their provision. What is considered as extravagancy by some people is not considered as such by others.
Allaah knows best.