Help take care of my sister kids

Hello my name is shaqwana bell and my oldest sister passed away at the age of 29. She left behind a 11 year old and a 4 year old. My uncle is currently taking care of them right now i wish i could help him out more with them but my financial situation is not so good right now. Im not working and i dont want to put so much on my uncle thats why im asking you guys for help please.