My mother is 89 and lives alone and does very well and in good health but very hard of hearing and wears aides but at night she swears she hears my brother singing behind her house and carrying on with a woman i have gone to check and found no one?

Bless your mother who is living alone at 89 years old. Since you've check that your brother is nowhere to be found around the house, let's assume that mom is imagining the late night escapades. It happens, from time to time, at her age.

She is experiencing auditory hallucinations, commonly seen in individuals with hearing loss. Best would be to have her examined by her primary care doc, who will be able to rule out possible medical causes and also try treatment that will allow her to rest properly at night.