GM, It takes time, but I do know that you, your boys and your father will get to the other side. I'm sure that you and your family miss your mother very much...but remember, she's always there w/you, i.e., watching over you.
I think going to London and Paris will do all of you a world of good. You have plenty of time to plan your trips and your father will be right there w/you to show you the best places to visit.
You and your family will be fine in time...please don't try to rush the process. Grieve when you need to and then release the pain. Do not feel that you need to smile 24/7 because you don't. All of you have had a number of losses over the last year or so. Shedding tears, feeling sad, are all part of the process.
Hang in there.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.