Guest list is falling apart

Long Post.
So i thought 2020 was going to be an amazing year. But with the virus, stress and now having my office closed for right now due to the virus is just getting to be alot.. on top of thag my fiance and his dad had a falling out and have not been able to reconcile. In the past they have had a rocky relationship but the last few years they really had a strong relationship. Now this falling out really put the nail in the coffin and they havent spoken.
We also recently got into an argument with his sister, and her and her fiance have dropped out of being in our wedding party but want to attend as "guests"
The dilemma is, we already sent out save the dates. When we were planning last year his dad planned on offering us money, which then we allowed him to invite multiple friends weve never met and very distant family members that we dont have relationships with. We dont care about the money, and will be fine wedding planning without it. But if he decides not to attend what do we do about the people he wanted invited? Weve never met them and feel it would be super odd to have them at our wedding if his dad isnt there.Overall 2020 has sucked big time, its all becoming a bit to much. Im starting to feel wedding planning is more of a hassle and with all this drama i feel like nobody cares. Ive talked to multiple friends and they have assured me that everything will work out and that the people who care about us will be at our wedding and thats all that matters. Im trying to keep positive. But id love some positive words or advice