Why does LibreOffice become unresponsive on my brother's Windows 8 computer upon the primary window appearing?

My brother has just recently installed LibreOffice onto his computer, whose operating system is a sixty four-bit edition of Windows 8, for the first time, and whenever it executes, at least with LibreOffice Writer or the hub component (my brother has not tested any of the other components), after the splash screen disappears and the primary window appears, LibreOffice becomes unresponsive, making it mysteriously unusable (at least for word processing). However, this issue does not occur with our mother’s computer, whose operating system is identical to my brother’s computer’s, or my computer, whose operating system is a sixty four-bit edition of Windows 7.

The sixty four-bit edition of LibreOffice’s latest version (version 5.2.1.2) is installed onto all of the computers.

Please try resetting the user profile, sometimes solves strange issues.
https://wiki.documentfoundation.org/UserProfile
Usually it’s enough renaming/deleting the file “user/registrymodifications.xcu”, it affects all the options in Menu/Tools/Options, and the files “user/basic/dialog.xlc” and “scrip.xlc” are overwritten, additionally custom colors in “user/config/standard.soc” are lost.

This has been attempted, without it affecting the issue. I doubted that it would have done so, because LibreOffice had always experienced the issue ever since it was installed.