It is quite possible that your husband is suffering from after effects of stroke.
The long term effects depend on the part of brain that was involved during stroke. Cerebellum controls our balance and coordination, If cerebellum is affected the person will have a tendency to lose balance and fall. If the right hemisphere is involved the patient may present with short term memory loss, impulsive behavior etc.
Since you have also mentioned about family history of Alzheimers disease which affects memory as well.
Please schedule an appointment with a physician as exact cause can be identified only by a clinical exam and tests.