You would have to be more definite in your questions about what InDesign does to answer your question.
I'm not aware of any way to convert a Ventura file to an InDesign file.
In speaking with the user, they use it for designing " all of our forms, brochures,
bus. cds, etc. We have hundreds of forms and bus cds. that we use in Venutra."
Everything will basically need to be rebuilt in ID.
If there is any good news, it is that prior to version 10 of CVP, the source text files are (generally) not embedded. The flip side to that is they will be tagged with Ventura's codes. These codes can be stripped in ID using Find/Replace or in the source application that produced the text.
I have moved a lot of CVP documents of all kinds into ID and QXP. It's work, but done once. One possible work-around might be to PDF some of this and use Markzware's PDF to ID. I have not ever bothered trying this, but maybe for some longer documents it may be a bit faster than manually moving a publication into ID. But even doing tech manuals of greater than 400 pages isn't that onerous.
The biggest hurdle you face is the employee. I doubt this person is going to like change. And there are certain features in CVP that have no correspondent feature in ID. Like side by side paragraphs if they are used. Running headers/footers are better handled in CVP. Same with image captions, figure numbering, etc.
But like I said, having moved years and years worth of various types of publications from one to another, it is all doable with a little sweat (and maybe tears).