Welcome to HCM
Sleep Apnea is abnormal cessation of breathing followed by disturbance in sleep, individual wakes and then resumes the sleep. It may be Central Sleep Apnea and Obstructive Sleep Apnea
. Basically it causes multiple awakening in night and non refreshing sleep. Individual become lethargic, irritable due to the poor sleep. It is due to poor sleep he may have day time sleepiness and poor attention and concentration, which may cause memory impairment.
But as you have mentioned your wife is 63 years old, and she is experiencing impairment in Immediate Memory, basically in registration and recall. Immediate memory loss
is classically seen in Dementias most likely in Alzheimer's dementia. So individual with this disorder tend to forget day to day things, he may have intact past memory but immediate memory is affected most.
As per my opinion kindly visit a good Psychiatrist
and take opinion.
Thanks, Take Care.