Second situation first )) "If I had won the lottery,..." means that at some point in the past this person had a lottery ticket but did not win. The speaker is expressing a regret or a wish about something that could happen in the past but did not actually happen. "..., I would be rich" means that the speaker is talking about present but about an imaginary situation. Now, the first example is not that easy to explain, because there are rules and there is natural English. Although it seems more logical to say "He would turn 90 today", this is not what a native speaker would say in this situation. You probably won't find a rule for this in a grammar book, so just accept it as it is. The possible reason for the use of ''He would have turn 90 today'' could be to further emphasize that he is dead (unfortunately) and it's a done fact. Compare to this example, "He would/could turn 90 today, except it's not his birthday today. His birthday is actually tomorrow". In this example, we're talking about a person who is about to turn 90 and is still alive. Hope this helps ))