If you were a boss who had a worker who was going through a family members death but making alot of mistakes along the way

where I work you get 3 days automatically

if you came back and couldn't focus I'd take you to the side and kindly tell you that you were messing up a lot and ask you an honest question: "do you need to go home or do you need to be here so you aren't at home?"

If they need to be here..I'd give them the Simplist of tasks so they could keep their brain occupied

if they needed to go home I'd tell them we'll cover this for you - and you'll do the same for us when we need it.

Send them home with pay. People deserve time to grieve and society gives them nothing to begin with. A little kindness goes a long way.

Talk to them and see if you can help. Maybe offer some counseling.

Probably send them home.
Otherwise others are having to waste time correcting what they've done