Glad things are good between you two but you're right - this will have to get addressed sometime..and sooner rather than later. Going on and pretending like everything is perfect is not realistic and its going to catch up with you two. I'm so glad you've reconnected again - but ya - you're gonna have to face the fire at some point.
Give it a couple more days like you said - hopefully he'll have come around a bit by then too.
Approach the subject with humbleness and without hostility or high defenses. When one person goes on defense - others sense that and their defenses go up and no resolution is found.
But ya - remind him that this wedding is for the both of you - and not his family. Nevermind the financial side of it and this completely A$$inine to forfeit more cash to accommodate his family. I'd also be pointing out to them how much money YOUR family has lost in this whole mess!
Unless of course they're willing to foot the entire bill!
If that were the case - I'd be like "cool - I'll get married wherever you want as long as your paying for it!".
It is completely ridiculous that all this drama is over such little money...and you mentioned inititally that they're fairly well off..even paying for your FI's sisters wedding.
Cmon..I'd love to throw that in their face and see what they come back with.
Just remember that you're NOT being unreasonable with your expectations.
I find when there's tension and differences of opinion - and you need to talk it out - your approach 100% reflects how the conversation will go. If you approach him and his family with the intention of mending fences to make everyone happy - they'll see that you're not the enemy and you're trying to find a solution that works for everyone.
I think you also need to give yourself some time to 'cool down' too. Because if you come at him and/or his family with anger and hostility - you'll find yourself no better off than you are now.
Best thing to do is work things out with your FI first before even considering talking to his family again. You two have to be on a united front and you have to address that with him too. Explain that you respect that they're his family but you're supposed to be his family too and you feel like he's not on your side with any of this. Maybe ask him flat out what he WANTS...not whats right for other people..but just simply 'How do you want to marry me?'. Ask him to pretend there's no issues or drama and imagine what his perfect wedding day would be like. I think if you make him realize that this is all about you two..it might make him turn around and actually FIGHT for what he wants..and not adhere to his family.
Wish I could offer more advice - I honestly don't know all the answers here - its a very complicated and ridiculous situation. But it is what it is and you just have to deal and move on.
Keep us posted!
Good luck when you do decide to finally talk to him.