I have Purchased a WordPress theme. It has a child theme. But this Company keep on updating Child theme also.
If I Customize any styling or perhaps any functionality in Child theme, on subsequent update of Child Theme everything will be lost.
Can we also create a Child theme under Child theme in WordPress, will that work and will that be a good coding practice?
One of the main reason why wordpress introduced the Child theme concept is to preserve the changes even after the updating of Parent theme.
https://codex.wordpress.org/Child_Themes#Why_use_a_Child_Theme.3F
You should make changes directly to child theme and when they ask for the updating of the parent theme you should prevent the updating of child theme.
How to prevent it?
Change the Child Theme’s directory name or if they let you choose you shouldn’t update the child theme.
If the provided child theme is not so important to your work then I would recommend you to create your own Child theme.
That doesn’t work, and it’s horrible practice for a commercial theme to rely on child themes.
If you are absolutely stuck with it, rename the child theme to prevent updates.
Edit: Important – Make sure you rename the child theme in the stylesheet, don’t just rename the folder.