Responses
Well, either it's the random trope of 'I'm here because the plot needs me to be' OR we'll get some actual reason, like him being involved in interior designing too or maybe he's part of another part of the house-selling market or something. At least that would justify him being there, since he can help and knows what his sister and brother-in-law might want/need.
But, given how random his introduction/feelings for the uke are, I'm inclined to say it's the first option...fingers crossed I'm wrong. :v
Why is he there? Is he going to live with the happy couple? Did they just invite him out of nowhere to search a house for him too?
Why am I not understanding? lol