Possible Clues:

• Accommodation for relative in good and managed state, even
• Relatively level part of the house
• Accommodation allowance including fare originally between New York and LA
• Add-on for an aging parent
• Dividing subsidy, New York and Florida providing extra accommodation
• In good US city, managed even accommodation for senior
• Modest dwelling — evidently not music to grandad's ears?
• Accommodation for old sort of knot below pitch
• Old lady collapsed in annexe, perhaps
• Awfully angry about new level in extension to house