Can someone help with Backfill advice.

I had my home remodeled last summer, and had my fireplace chimney removed.

At finish grade level to the bottom of my foundation, the poured chimney footing remains. I started a project to knock this down with the sledge and clean this up a bit so I can get all of the poured chimney footings under ground so I can put my rock bed over and conceal it. Old reminients of the chimney were caved in and the debris filled the chimney (Dirt,Bricks, Concrete) .

I decided to go further and started to dig all of the debris out of the hole while I am at it though because after a heavy rain, I am getting some water in my basement through this area now. My whole home is poured walls except where the chimney is located is masonry block.

I am wondering when I get all of the brick and stone cleaned out of the old chimney what I should do to backfill it. I assume with all of that in there the water is getting down my foundation way to easily.

Once I get it all cleaned out, do I backfill it with sand? Any thing else I need to be doing to make this right? Any help you can provide will be greatly appreciated. Thanks!