too many plot holes.
1. hotels have lots of housekeeping staffs to clean and maintain the rooms. They would know for sure if their guests didn't check back in or missing even for one day.
2. The owner of the boat they rented too would search for them too in case they didn't come on time. And why they didn't have phones so they could track them, or in case they have an emergency.
3. The guy should have secure his family first before he transfer the money.
4. His family would probably die of thirst and hunger on that so much heat and exposure.
5. The Police are more focus on arresting the father than searching for the bad guys and finding his family.