Final answer:
Henry spends the night in Keiko's house in the relocation center.
Step-by-step explanation:
According to the provided information, Henry spends the night in Keiko's house in the relocation center when he goes to see her. This is mentioned in the given passage, where it states, 'The house stood there, splendid and solitary', implying that Keiko has her own house where Henry stays overnight.