It all started back in the 1500’s.
Lead cups were used to drink ale or whisky.
The combination would sometimes knock the imbibers out for a couple of days..
Someone walking along the road would take them for dead and prepare them for burial.
They were laid out on the kitchen table for a couple of days and the family would gather around
and eat and drink and wait and see if they would wake up.
Hence the custom; “holding a wake.