The assumption that the MC's family on his mother's side is loaded is quite the leap to begin with. We know absolutely nothing about under what circumstances ownership of the broken-down hotel was obtained.
If you are "rich" rich, as in you only really start to pay attention when its 8 figures plus, you don't buy a broken down hotel and then instantly move into it and subject yourself to the noise and dust and overall unpleasentries of construction work.
Everything we know is second hand and in some cases third hand knowledge and depending on the Value of the hotel at the time, as little as 5% of the value could have been enough to obtain ownership with the rest being borrowed capital.
So if the hotel was worth $2.000.000 it would've taken all of $100.000 to buy it, and with a sound buisness plan, have a bank or an investment group finance the rest of it.
So, we don't know if that side of the MC's family was or is rich, but everyone should temper their expectations, because from what we DO know...well let's just say it's not all that impressive or unusual.