Final answer:
A 68-year-old male showing crying spells, excessive sleep, poor hygiene, weight loss, and hallucinations following his wife's death is likely experiencing major depressive disorder with psychotic features.
Step-by-step explanation:
The most likely diagnosis for a 68-year-old male who presents with symptoms of crying spells, excessive sleep, poor hygiene, a significant weight loss, and hallucinations of seeing his deceased wife, all following her death, is major depressive disorder with psychotic features. Given his age and the recent bereavement, it is important to evaluate for depression, which can manifest with these symptoms in the elderly. Additionally, the presence of hallucinations indicates psychosis, which can accompany severe depressive episodes or be indicative of a condition such as depression with psychotic features or complicated grief. Due to the complexity of the case and potential for other underlying conditions, a comprehensive psychiatric evaluation is warranted.