How hard should it be to plan a simple birthday party?

Wow, you really made a mess out of this deal. Next time you will figure it out hopefully. You should have just made the plans and stuck with them and if people could have shown up, fine, if not oh well. You put too many cooks in the kitchen, as it were, including the guest of honor. Now you have a big mess stirring in the pot. Make plans to go to the upscale restaurant, kids or no kids. Have someone pick up your dad and take him there and then back to his own house. Let your brothers stay at the hotel and don't worry about them. Don't worry about the cousin, if she calls you or your dad both of you say that there will be no party and make up some excuse. Sheesh ! simple as that. The end. Oh yeah, and remember this - people who are 80 don't have the patience for all that hotel stuff etc. etc. it's too much excitement and nonsense for them. Keep it simple to keep it enjoyable for the person you are honoring !!