Okay, here are my thoughts, as someone who's just been through this class of drama:
1) the size question is not clear-cut. First of all, the "normal size" is just an average, it may not be "normal size" for you. Second, the measurement of an aneurysm can vary-- mine was estimated at 4.5 mm one time, 5 mm once, and 6.2 mm once, depending on the day and who was measuring and whether it was the MRI, MRA or angiogram they were looking at. Third, you need to ask the doctor, or look closely at your lab report, to clarify what they mean by 6 mm-- my suspicion is that's the total measurement, but they need to explain it. You also will remember from high school geometry that the area of a circle or the volume of a cylinder does not change in a linear relationship to the diameter, so you can't say 9 mm is 3 times bigger than 3 mm.
2) I have no idea what's harder to repair or where the best or worst places to have bleeding are. Whether you die, recover, or are significantly permanently impaired by a bleed depends I am sure depends on many factors, including your overall health, how quickly you can get help, how good the help is, how fast it's bleeding (apparently some bleeds just drip a little, some burst), your blood pressure, and who knows what else. Ask your doctor, but I bet you don't get a much clearer answer; no one wants to make bets on that kind of question.
3) The fear I can address from my perspective. I am not a religious person, so I can't invoke God here, but I know that helps a lot of people. I would say that first, you have almost certainly been living with this thing for years and years, and so chances are good you'll just go on with it for a few more weeks until a plan is decided on. If you look at studies, the chance of a rupture in any given year is only a couple of percent, so you figure during a month or two, it's less than that. You know it exists now, so if you get "the worst headache ever" or a seizure, you'll know to go straight to the emergency room, which you might not have before, and there's a doctor out there with some imaging, so you're in better shape than before in that sense. Next, this is a scary, but most likely fix-able problem. It's not terminal cancer or some chronic disease that will kill you slowly; almost certainly you'll get through this crisis and be the stronger for it.
I focused on three things during the pre-surgery scary time: 1) I thought very hard about how terrific my life is and has been, and tried to be grateful for it, just in case this was a terminal thing. I tried to relax and not ask much of myself otherwise-- no training for marathons, applying for new jobs, etc. Meditate, journal, pray, maybe. 2) I tried very hard to tell my spouse, children, friends, how much I appreciated them and needed them and what I hoped for their future, if I didn't get to live to see it. Show your love while you've got the chance (and maybe they'll remember that, when you're no fun to be around during recovery). 3) in some ways, you should go ahead and wallow-- if you were going to die from this, what would you want to have done? Write letters to your children, make sure your will is how you want it, tell your spouse where the important papers are, make the apologies you've been meaning to, take that trip you've been dreaming of....get as close to no-regrets as you can.
As for the kids, I would be very careful what you tell them and how you act around them, because they will look to you for cues on how to handle this and even future crises they may face as adults. The simple truth is a fine thing to start with, but you need to be calm as you explain what's known and what's not, and not over-promise either. You can tell them you're nervous, but you also need to tell them all the positive steps you're taking to ensure that you'll be fine. The younger children will worry about how this is going to affect their routines and their lives-- it's not that they don't love and worry about you, but they are innately self-centered: e.g., if you're sick, who will take them to school? If you can't work for a while, will there still be money enough to have cable TV?(dumb example, but you get my drift). Reassure them of your love and that they are your top priority. And share information about what's going to happen to you; when you get close to surgery, they may need to know, for example, that children aren't allowed to visit in ICU, or that you'll be drugged up and sleepy after surgery.
As for the wife, ask for her support in whatever way you need it. But you may also need to cut her some slack if she doesn't react the way you expect. I wanted my husband to get choked up and emotional and tell me how vital I am to his existence and that he was terrified I would die... but that's not his style. He goes more for the quiet "what can I do" approach to any crisis. I had to ask for an display of emotion, basically. Some wives are going to be sick with worry about how life will be for them and the children if you die or are disabled, so you may need to comfort her.
Finally, you could ask the MRA people to call you if they have cancelations, that might move up your July 7 date.
I hope some of that helps. I am so sorry anyone has to go through this. It was such a shock for me to go from being just fine to scared I could die any ol' second, and even in recovery from surgery, I still have some fears. Post again here, if you can.