Mr Cross's appeal against the decision has been rejected - despite the inspector admitting feeling "profound sympathy" for Mrs Cross.
The bungalow - which would have been built on Mr Cross's own land at Cliffe Lane Farm, Cartridge Lane, Grappenhall - would "substantially and harmfully reduce Green Belt openness", the inspector has ruled.
Mr Cross applied for permission to build the bungalow because his wife suffers from a rare condition, Multiple System Atrophy, which is expected to continue without improvement for the rest of her life, with a progressive loss of mobility. She is largely confined to a wheelchair.
He needs to live on the site to run the farm and also to care for his wife and also needs accommodation for an overnight carer.
The existing farmhouse is not suitable for conversion because the ground floor is on a number of levels with internal steps and also has steps leading into the house. Other farm buildings are also unsuitable for conversions and there is a sloping, cobbled yard which would present difficulties for a disabled person.
But the inspector says the possibility of extending the farmhouse, or an adjacent semi-detached property occupied by Mr and Mrs Cross's son, has not been explored and that personal circumstances carry little weight.
Andy Farrall, Warrington environment director, said: "As in inspector noted, it is impossible not to feel profound sympathy for Mrs Cross and the impact her illness has had on her and her family.
"Such a predicament, however, is person circumstance - which does not amount to the very special circumstances needed to outweigh the harm to Green Belt in this case."