Menu on mobile closes when Custom Link menu item clicked

I have a problem with the menu on a site I’m working on. I have a few top menu links, but they don’t have any pages. Instead, they just display a sub menu when you roll over them on the Desktop version. The problem is on mobile devices. Obviously you can’t roll over so instead, if I try to click on the same top menu link, the menu just closes on me. The only way I can get the sub menu to appear is by clicking the very small down arrow to the right of the menu tittle, which can be hard to do on a small mobile device.

Is there any way I can change the functionality for mobile so that when I click the top (custom link) menu item as well as the down arrow, the sub menu appears?

Here’s a screenshot showing the 2 menus and what is happening.
https://snag.gy/tJmAYC.jpg