Four movements, ten minutes, plus a list of what not to say. Short: the family is exhausted and the sermon is not the reason anyone came.
Name the person, and say the death is real
2 min[do not soften the fact - the room already knows and pretending costs you trust]
[the person's name, and one specific true thing about them - not a summary of their virtues]
Then say plainly that this is a death and not a transition, a passing, or a journey. The family has spent a week being handed euphemisms and there is an enormous relief in one person in the room saying the actual word.
The text
2 min[a lament, not a triumph - Psalm 23 or John 11]
[read Psalm 23, or John 11:32-36]
If you read John 11, land on the two words. Jesus wept. He is four verses away from raising the man and he cries anyway. Whatever else that means, it means grief is not a failure of faith, because he had all of it and still stood there crying.
What not to say
not preached[for you, not the room - these sentences do real damage]
Everything happens for a reason. God needed another angel. At least they are not suffering. They are in a better place. God never gives you more than you can handle. She would not want you to be sad.
Every one of these asks the bereaved to stop feeling what they are feeling in order to make the room more comfortable. People remember them for decades, and not fondly.
The turn and the close
5 min[hope stated, not argued - this is not the room for apologetics]
Say what you believe, once, plainly, without defending it. A funeral is not the place to make the case. It is the place to state it and let people take what they can.
[your material, 300 words - and one thing the family can do this week, because the days after a funeral are the hardest and nobody warns them]
Close with the name again.