Jennifer's mother Darnell Donaldson, brother Jason and seven-year-old nephew Julian King were murdered by her sister's estranged husband William Balfour in 2008.
The 34-year-old songstress and her sister Julia celebrated Julian's 15th birthday by giving charity, reported ET online.
"I wanted my sister to look forward to her son's birthday. My mother always told me, 'What I love about you is no matter how negative things are, you always seem to find the positive.'
"Julian was a scholar of a child. He was a giver as well. Hatch Day represents everything about him," Hudson said.
"I had no idea what we were starting, and so to think back then to now, it's like, look at the seed we have planted!" she added.