B.C.
My condolences for your loss.
You might need a grief support group to help you through this.
My FIL died suddenly from a heart attack.
He'd just got back from touring New Zealand and no one expected it.
There was no warning and no one had time to prepare or be anywhere.
It threw our whole family and it took awhile to get over the shock.
My godfather died suddenly - also from a heart attack.
He'd gone out to do some shopping for Christmas presents on a day off from work.
He was stopped at a stop light and when the light turned green - his car didn't move.
Finally someone came up to see what was going on and he was slumped over the steering wheel already dead.
If anything can be said to be fortunate about it was - at least he didn't crash into anyone.
There's really no best way to go.
Long sickness, expected vs suddenly, unexpected - it's still a tremendous shock and makes such a hole in your life.
There is no set time table for grieving - it will take as long as it takes.
Eventually you will be able to remember the good times without crying.