My condolences on your loss - I lost my wife last year, and I know how traumatic it can be trying to tidy up a life partner's affairs.
But this isn't the right place to ask for this help: we aren't a recruitment or "code it for you" site. You need to look a lot more locally, and a lot more specifically (particularly if the old DG equipment is still in use, I haven't touched one of those since the mid 80's!).
I'd suggest that your best bet is to try somewhere like
Hire Freelancers & Find Freelance Jobs Online | Freelancer[
^] and ask there.
But be specific (or as specific as you can) and remember: if you pay peanuts, you get monkeys. And there are a lot of monkeys out there! :D
It may be a better idea to bite the bullet and get a new system created for modern hardware and software using the existing one as a "specification" rather than trying to get the existing software supported: after all the years it's been running it's probably going to be pretty difficult to understand the code - which makes it difficult to support. A new system also gives you access to a lot more developers for future work / support.