There are plenty of applications created with Delphi, that are conform with 62304. My own application for example. 62304 does not demand the use of certain languages, it does however require extensive documentation. Documentation you should have anyway... Have you read anything concerning this standard? Wikipedia grants us a small glance at the implications: https://en.wikipedia.org/wiki/IEC_62304 I would suggest to consult more in depth literature and courses however. The subject is not trivial, especially the risk based decision model, that should be used in almost all aspects of the software life cycle. Auditors or accreditors as you call them, will not read your source code, as that is proprietary to you and your company. They will however read the entire technical documentation.
Most important is the market you want to sell your product, if it is Europe, you will need more that IEC 62304. You will need to adhere to the medical device regulation (MDR 2017/745) and that means you'll need to establish a company wide quality management system such as the ISO 13485. And you'll need certification before selling anything. All in all this will swallow up a ton of money before you can even start thinking about generating any revenue.