Sorry for the delay in answering. We’ll try to help you with your site.
But we faced some problems while trying to login to your Dashboard and connect to your FTP.
1) Once we trying to login to Dashboard we get auth window and can’t pass the authentication. http://prntscr.com/mn7837 What is the username and pass?
2) FTP directory is empty http://prntscr.com/mn78o6 So, check the destination directory of our FTP user.
Once you provide correct info we’ll be able to proceed.
We have fixed the major issue that you get after the update (we edited php and CSS files of your child theme and also mu-plugins/index.php because your developer added a few theme functions there). You have a lot of changes in your child theme. If some CSS styles are still missing you will need to check the code that you added before and make sure that all the classes are correct in the previous code because we change the structure a little bit and I’m not sure if all the styles are correct on your site.