What Causes Recurring Fainting Spells?

Hi, My father in law has had a mini stroke about 4 months and over the last month has fainted in the garden in the early morning while getting the newspaper at least 3 times, with the last one (two days ago) he blacked out. He can t remember fainting or walking in to the house, only walking to the front door and then sitting at the table eating his cereal. he wear bare feet too on a tiled floor and concrete pathways. He lives with his wife, but in my opinion she is not taking this seriously, as she has never call a doctor or ambulance for help. Plus they go shopping afterwards, he drives. I am concerned of a planned ocean boat trip to New Zealand, they are leaving in 5 days. I know that he needs to see a doctor, but I can t get the family (all four children) to stand up and take control of the situation. they don t want to upset anyone. if you have any advise, please help. I feel that their attitudes are going to see their father dead before he should be. He is only 89 and still smokes (but in hiding from his wife)