I have a problem in understanding a sentence in <The Curious Charms of Arthur Pepper>

[blwings]

I've just started reading Phaedra Patrick's <The Curious Charms of Arthur Pepper>.
On page 8, I faced the sentence below.

"After over forty years of marriage, it was just him in the house now, with its three bedrooms and the en-suite shower room that grown-up daughter, Lucy, and son, Dan, recommended they had fitted with their pension money."

I understand that the house he is living in now, has three bedrooms and the en-suite shower room was recommended by his daughter and son.
The part I don't understand is what they refer to? Lucy and Dan? or the bedrooms?

Please help me to get through this book.

[Danik 2016]

I don´t know the book.
What I understand about this part of the sentence is that Lucy and Dan want to fit the bedrooms with their pension money.
They, IMO refers to the bedrooms.
I agree with you that this sentence is somewhat ambiguous.

[North Star]

They refers to the people to whom Lucy and Dan recommended the fitting of the shower room, that is, the widower dad and his late wife, using their (the widower dad's and his late wife's) pension money.

[Danik 2016]

Yes, that makes sense. But the sentence is ambiguous. Is there a former sentence that clarifies this meaning?