First, be aware of the two sources of advice in audiophilia; the "good enough" camp, which are typically budget audiophiles, and those who seek a premium experience wherein cost is a secondary consideration.
Your system and listening will vary widely based on whose advice you accept.
My condolences on your loss; September 9 will be the first anniversary of my father's call Home. The sting of death can be acute; if you wish to chat privately, I invite you to do so.
Please do not take this next thought as though it is callous; an audio system does not care whether you have emotions, ties to the equipment. If your goal is to continue in the vein your father did, with similar amplification, etc, that is a personal decision, but such decisions do affect performance. Like persons who feel obligated to the deceased to hang on to inherited stock and not sell it, even if underperforming, hanging on to the inherited amp or a similar genre of amp may give you a less rich experience.
You will get many responses with a very wide range of recommendations. You will likely end up more confused at the end than at the beginning. But, that's ok, you select your preferences and move ahead. Choices are open-ended in this hobby, changes readily available. If you don't want to wade through all this, then go to a dealer and let him/her give guidance. My advice in regard to preferences and amp selection is this; if you put a lower powered tube amp on those speakers, you will get a more warm, syrupy sound with less resolution, a more romantic sound. I suggest you stay away from SET (Single Ended Triode) amps, as matching them to speakers can be tricky, and frankly, imo several aspects of performance lack unless paired with different, even more efficient speakers.
If you go higher power solid state, you should hear more dynamic impact, more taut bass, but potentially with more upper end presence and perhaps too much stridency for you. Only a listen would tell; no one here can declare/predict what you would prefer, and only a setup with an amp would suffice to show what satisfies. There is a very wide range of amp performance with any given speaker, so do not accept anyone's claim that they know the "perfect" amp for it. I suggest you attempt to get on loan a couple different genres of amps to try against the Richersounds.
If you want to make it a project, a hobby activity, look for local amps you can buy and try. You will be astounded at the difference in outcomes. Then, as you wish to upgrade the system, you can have fun with all sorts of changes, including cabling (Power cords, interconnects, speaker cables, etc.) source, etc. It's a beautiful hobby and many ways to play, i.e. collector of media emphasis, or "gear head" who rotates gear. I love variety, so the speaker would be one of several different genres, or I could rotate DACs, or if I used analog I could have a turntable with several arms and cartridges, etc. I hope you find great joy in the hobby as did your father.
I am a reviewer, so I point you to my article on an amp of particularly high sound quality in my experience, the Legacy Audio i.V4 Ultra (can also be configured as i.V2 Ultra, which would mean a two channel unit, or it can come configured as Monoblock, with one channel per amp) at Dagogo.com.
The amp I have recommended is a class D design, and some here will rail against that. So be it. I have no interest in arguing with anyone on my recommendation.
