The only reason I would suggest that the Holloways take a break back home for awhile is for their physical and mental health. Maybe a week's break. They do have another child who needs their support right now. Beth looks like she is on the edge of a very serious breakdown.
Eliz. Smart's mom did this every so often during the investigation and search. She let other family members take over. She was criticized for this, but she had other children to think of.
Are we sure that Aruba would let them back in once they left? That's what I would be afraid of if I were in her shoes. But you're right. They DO need a break.