He doesn't seem that incompetent to me. He's trying to meet the housing demands for someone who has special needs. Finding wheelchair accessible properties in the right area, for the right price isn't super easy in the real world(speaking from experience here), let alone one with accommodations for a mermaid.
Tack on that he has to look in one of the most cramped and in demand housing markets and it doesn't seem so bad that this is all he can come up with so far.