Need Advise - Family prob - LONG!

OK - so my brother and I haven't really spoken in a few months BECAUSE..... he is 38 years old and my nephew is 12. Last year for my nephew's b-day (which is 2 wks after brothers) my nephew SO wanted a really expensive present (like 400.00) so brother said to me, I can't afford it if you want to get it you can - so I did. I love my nephew and neice like they're my own. Well, because I got nephew such expensive present, I did not get brother present. Just was with him on his b-day sang, blah blah blah. WELL a few MONTHS later he decides to tell me that this bothered him and he thinks I'm selfish, only worried about myself and my wedding... If I couldn't buy him something then I shouldn't have bought nephew that gift...and stay out of his life. OK - I tried to explain to him that he's the one being selfish - wanting to take away from his child so he could have something more. ANYWAY - he is also not talking to my mother(long story about his parenting skills) and we've all had some nasty fights over the last few months. SO - what this has to do w/ my wedding.... FI DOES NOT WANT HIM THERE! He has called me vile names and has ZERO resect for me and my mother - and neither do I But, I know because of family politics, he should be there. My neice and nephew are both in the bp. My brother and sis-in-law have been divorced and he is refusing to pay any $$ towards her dress or his tux. AND FURTHER he is refusing to p/u neice's dress from bridal salon - since April! Ex sis-in-law is being pretty good, but it burns my a$$ that he is doing this - so, invites went out 2 weeks ago and his is still sitting on my desk. I was going to wait until the very last minute to send it JUST to be spiteful, but I know that really won't matter to him. Him and his girlfriend will just show up empty handed and I really don't feel like dishing out $300 bucks for the 2 of them. BUT if I don't invite, then he will most likely cause problems w/ neice and nephew being in BP. Should I just s^ck it up and invite him and ignore it all???????
Sorry if I was all over the place with this - it's been VERY frustrating over the last few weeks and I just needed to vent