IF his hearing problem is simple volume loss, and do get a professional audiologist to evaluate his hearing, then AirPods can help at considerably less cost.

Here are some articles on the matter.

https://www.ncoa.org/adviser/hearing-aids/airpods-hearing-ai...

https://www.forbes.com/health/hearing-aids/airpods-hearing-a...

https://www.techradar.com/how-to/how-to-use-your-apple-airpo...

If the problem is diagnosed to be complex, follow the doctor's advice. I can't speculate on how to evaluate/compare different prescription options that may be offered.