It will be good that you provide a URL of the website that you are working so we could figure out what is actually wrong with your website, as hovering over the menu is working in our themes.
and to make disable selecting the parent menu you can provide a link with a # tag. The Methods to do this are as follows:-
Go To Appearance-> Menu.
On the Left side of Menu You will see Pages, Link, Categories etc.
If Link is not available you can go to Screen Options at the top and choose Links.
In Links you could found URL and LINK Text
In URL Insert # and in Link Text Name the Parent Menu Name