Technically, no tool (also not HTTrack), will be able to download the actual
source code behind a website running. The HTML artifacts might often be
already a pre-processed result based on something like "original source code"
and application code, which creates and/or assembles together the pieces,
which then become what you see as result, the website.

HTTrack (and any other client accessing a website) will only get to see the
resulting "intermediate source", which gets rendered in the web-browser - and
if you save this it's some sort of snapshot/static copy of the webpage.

Interactive elements may or may not work locally, but that's up to how
JavaScript has been put in place.
If there is any interaction with a "backend server", this is what will not be
possible. There is no way to access and copy the whole website including its
backend setup. Not to mention that would be in most countries not
appropriate.

Since that looks like a NPO-driven website and you are in
the education sector, it might be an idea to reach out to the website owner
and try to see if you can join in any mutually benefiting collaboration with
them.

Good luck!