I'm so upset...Family dilema and I don't know what to do.......

I am posting this under a different screen name because of the sensitivity of this issue. People I know chat on this site, but trust me, you all know me.....

OK, I'll try not to make this too long but I have been losing sleep over this.

I got married last week at a place where my cousin and her DH work. My cousin was my MOH. They are waiters there on the side (weekends) and they both work full time during the week. I sometimes also worked there when they needed extra help so I have grown to know a lot of the people there.

My dilema..... DH and I put aside $300 for tips for the reception hall. $100 to the bartender (who is a good friend of mine), $100 to the Maitre D' (I had 50 people and the rule of thumb is $2 per person right?), and the last $100 to tip the staff of three people, two servers and a busboy. Well, during the reception my cousin's DH came to my DH and told him he would take the money and make sure everyone got tipped. When he saw the $300 he told my DH that he should throw in an extra $100 because everyone did a really good job. Without even thinking DH gave him and extra $100. And told him how to tip everyone; $100 to the bartender, $150 to the Maitre D' and now an extra $150 for the staff of three.
So last night I find out from my friend who was the bartender that he only gave her $50 and made a comment about him having to 'pull' it out of my Dh because he was so cheap

Then she tells me he only tipped the staff of three $25 each

So where the F*** did the the other $275 go!!!!!!! I think he took money and kept it for himself!!! This wouldn't surprise me because of other very slezy things he does, but it never effected me before.

DH is away on business so I haven't be able to talk to him.

What should I do??? I have been up all night so upset over this!!! This is my family and my cousin and I are like sisters.