Advice on what to do with symbols that are not blocks?

Hello, I'm in need of advice.

A consultant (of our office roofing department) provided CAD drawings of roofs depicting various roof symbols to represent equipment, this survey was years ago so I had no hands in it. The office roof inspector is hoping I may be able to change all the symbols to be industry standard symbols as the consultant used their own. Originally I told the roofing department it would be easy as I would just write a lisp and a script to change all the symbols to the new blocks...or so I thought.

As soon as I opened one of the consultant's files, those symbols...were not blocks, they were all comprised of lines, circles and hatches. In my frustration, I contacted the consultant and wanted a clarification on this, I got an apology that they simply drew the lines in and copied and pasted the symbols over and over again.

I got 240 drawings to literally update overtime. Each drawing can have an average of 30 symbols. I was wondering if anyone has ever dealt with such an issue. Do you have any suggestions for me other than to shoot the consultant? kidding of course. Is there a way for autocad to recognize certain line patterns or hatch patterns (actually only the solids were used) and then store the x,y co-ordinates? Anything would be appreciated.

Basically you want to replace an old symbol (which is not a block) with a new block and you want the insertion point to be a certain (fixed) coordinate?

I doubt this is possible. You will have to manually replace the lines/symbols with your own blocks individually.

If the files aren't used anymore I wouldn't bother updating them at all. Then only update them as they are needed.

You could always outsource it to India etc (or get the junior draftsperson to do it) which is ridiculously cheap although the quality control check would need to be good.