If you need proof, his
biographer says that Jobs did not believe in charity:
Note that when he was at NeXT, Jobs did start a Steve Jobs Foundation that supported vegan research and such, IIRC. The guy running it wanted to do more social stuff, but Steve had no interest or time for that, and before long, he shut the foundation down for good.
This might be a good read for you (if you haven't already read it):
http://dealbook.nytimes.com/2011/08/29/the-mystery-of-steve-jobss-public-giving/
It is a bit dated, as Apple now does have an employee matching program, up to $10,000 I believe. Also, I'm a bit surprised that it doesn't mention Apple's support of ProductRed (for years) for aids.
It does however, show some of the many things he has done to support causes (while not financially) at least with appearances, support and legally.
Also, there is a very high possibility that he donated anonymously, as the article also talks about - especially given how he likes everything to be private.
At the end of the day, it doesn't matter. Whether you're a millionare, billionare, or an average Joe - nobody is obligated to donate money.
I personally don't like to donate money to charities. I like seeing my effort directly, I do a lot of volunteer work or donate toys, food drives, etc.