Need some nav menu help please

I am helping a friend out with his website and no matter what I do I can’t get the menu to display right. He paid someone to build his site, and it has some type of style on the Nav Menu that is blocking any type of Child or SubMenu to display properly. it simply shows the SubMenu as a bullet style item with text displaying rather than allowing it to be nested or as a dropdown menu. I am leaving the site with the menu showing what I am dealing with. Here is a link to the site https://www.wiwgroup.net and I am trying to make the Balconies as a SubMenu to the Projects and have it dropdown. I have tried making a new Navigation Menu and it displays the same way so I know it is a CSS Style conflict. If you view the page on Firefox, Right click and select (Inspect element) you can look at all the style sheets etc for CSS and everything. if you need me to copy and paste any code I am happy to provide that as well. I am just at a loss as I am used to using DreamWeaver for website and I have not found any way to do it properly with WordPress. Thanks for any help and support I can get!!

[Moderator Note: No bumping, thank you.]