If you decided to make charity campaign, publicity and transparency should be main thing. After all, all these money were donated by people, it's not your own property. If I would do such thing, I would try to keep receipts of every purchase and add record of it to spreadsheet. Because it's not enough to add vague information that $50 were spent on potato or $100 on rice without any receipt.
I'm surprised that this charity has been running for almost two years with approximately 2
BTC+ donated and that there are no single receipts of items purchased, only some random pictures of foods and packed items that could be obtained from the internet (I'm not accusing anyone, I'm simply stating the possibility). If C13 was able to withdraw $500 from the charity account for medical care without the authorization of the donators, it's probable that some of the charity funds were used for purposes not mentioned above. I don't know C13's financial situation, but it's risky to put such a large sum of money in the hands of someone who isn't financially sound...
What I unlike most in this situation that these users don't bother to reply to accusation properly and seems that they don't give a shit about it. And coincidence or not, but soon after accusation they become basically inactive on forum.
They do not give a fuck they are somewhere drinking beer and laughing at our comments after all nobody is going to jail.