With the long list of other medical concerns he has I would check out other possible causes. It could be a function of exhaustion, anxiety, medication, alcohol, vitamin deficiency... It could also be a TIA (mini stroke), or other medical condition. It doesn't have to be EOAD. There are many treatable causes for such lapses of memory.
EOAD not only affects memory but all other cognitive function. You will see personality and behavior changes, difficulties with spacial thinking, changes in his ability to solve problems and follow directions, withdrawal, poor judgement, inability to retrace steps. Many of these changes will be noticed before the memory loss is noticed.
If he remembers quickly what he has forgotten or can retrace his steps to find that memory again it is probably something other than EOAD. My best suggestion to you is to talk to his doctor related to his memory lapse and see if you can find the real reason for the episodes. It is better to be checked out and know for sure then to remain fearful not knowing
I do hope it is something fixable and simple!!