I looked for an answer at the website USGovernmentSpending.
As a rough approximation, the overall U.S. government spends:
- 20% of its expenses on health care (70% of that on the elderly, 30% of that on children)
- 16% of its expenses on education (50% of that on children)
- 8% of its expenses on welfare (13% of that on the elderly, 87% of that on children)
- 19% of its expenses on pensions (100% of that on the elderly)
So the elderly get roughly 34% of the government expenses overall, and children get 21%.
Wanting more reliable answers, I started doing some searching and found an urban myth popular last year People who refuted that myth found that the best answer is "the elderly receive about twice as much" but there are details of timing and categorization.
Another essay claims the real issue is the middle class. Families must care for both their children and their elderly parents. Perhaps the real issue is how the government promotes this happening.