Fougasse just said what I had planned to say about what a 'piper usually does at a funeral.
I usually find a tree to stand under, and stay at a distance from where the people will gather. I once played at a cemetary which was right behind the church, and walked in front of the hearse the short distance that it had to travel.
What I'd suggest is when you talk to the 'piper, tell him/her when and where to be, and he/she will figure out how to choreograph it. The funeral director usually comes to me at the graveside and tells me the order of things, and nods or waves to me when it's time to strike in. I know this all sounds kind of loose, but it's always worked out fine.

Your family is in my prayers.