Accordion as a lateral menu

Hello. A client has a “frankenstein” site on WordPress. I mean, the developer don’t know anything about WordPress and he created the content with php/html files and created the products with posts. They also have outdated PHP.

My questions:
Is there a plugin to create accordion menus other than Bellows Acordion Menu?
Is it convenient to use a regular plugin for the creation of accordions for a lateral menu?

I’m asking that because I use Bellows Accordion Menu, but it doesn’t work with the version of PHP the client has. The client does not want to update PHP at this time, since the site was built in an unusual way and the update could “break” her site.

Thanks.