Alex was rushed to the hospital overnight with an infection.
His father John Onkle says, "Last night he started running a fever."
His health took a turn for the worse. And though he wanted to come here, he needed to go to the hospital.
Alex is fighting a rare and aggressive form of cancer, for which his mother says there's no cure.
We spoke to him Thursday about the party and all the people pulling for him.
He said, "It really does help me out to make me feel good. So I think that would be really good for me."
In the end, he was just too sick to attend. Organizers were devastated.
Organizer Pat Crew says, "We were ready to cry. And we just decided to dig our heels in and stick it out and hope people's hearts were where we wanted them to be and they are."
The party had a second purpose to raise enough money to allow Alex's mother to stay home from work with him, and her other four children, for a few months.
And for that reason, the show had to go on.
Jean Reel donated and says, "I said to my husband we've got to do something for this little boy."
People opened their checkbooks and some like the Wentzville Mayor donated something extra to the cause. He agreed to shave his head if organizers met their financial goal.
Mayor Nick Guccione says, "Small price to pay to help a family and a little boy."
They hoped to raise $10-thousand dollars. In the end they raised more than $18-thousand.
His family just wishes Alex could have been here to see this.
John Onkle says, "Love is stronger than cancer." He adds, "It's just great the way everybody turned out here. It's actually unbelievable."
The organizers took lots of pictures and video of the fireworks for Alex. They plan to bring it to him at the hospital tomorrow.