The youngest granddaughter might be playing up a bit - losing a father figure no matter how is probably hard to process.
You can buy long rolls of drawing paper - might be worth getting one of those and encouraging her to colour / draw on that instead? Though she may be doing it for attention too because she feels a bit vulnerable.
I'd encourage them to go outside more too. Do you have space for any second hand play equipment in the garden? Or ask if you can take them out.
In terms of mess - do they have any storage to tidy things up into? My house was bad until I bought some units then everything had its place. I'm not saying it's okay to be messy - just easier to be tidy with a dedicated area for things. Otherwise like others have said, encourage dialogue around how long this will be and talk to her about what is actually bothering you.
What decade were your grandparents born?
Desperately sad story of the assisted suicide of a grieving mother
What's going on , on the street outside your home right now?


