Do you need to put yourself through this?
Can the friend do the handover?
You seem very vulnerable and raw.
He sounds horrific.
Plan the physical logistics and then the emotional preparation.
Can you meet to handover in a public space - so it’s neutral territory eg car park and quick
Or can you decide not to go in the house?
Google grounding exercises and breath techniques - to dial right down your stress and anger for the x minutes handover.
Chanel a bright breezy efficient busy receptionist - the task is to shuffle your DC over calmly and quickly and be gone. Concentrate on your DC - they shouldn’t be able to sense your stress as they have enough of their own.
Imagine you are wearing a thick glass dome over your head where your exs words are distant and fuzzy.
Don’t get drawn into any conversation - just v short vague vanilla responses to close down any conversation “Will come back to you on that”
Your indifference to him will sting
Silence and detachment are powerful
Style it out - don’t let him provoke you to giving him anger, negative or anxious energy.
Good luck.