Has anything changed as far as the household routine goes? Has she been having less time with humans? Sometimes if a bird acts aloof, humans will stop interacting with them as much, and this creates a vicious circle, sadly. Has he tried simply sitting by her cage while doing something else, such as reading or checking his phone? Sometimes birds just need to know you're there and trusted (and it takes them much longer than it takes humans, sometimes). A vet visit would be ideal, but I understand your concern also.