Ron, not familiar with Elements, but it certainly has been around & as you can see even with these few comments, highly regarded. I use Affinity & find that it certainly does what I’m capable of doing with it & I know it can do much more. I use Affinity in special situations, stacking, stitching panos. With my Astro photography I use a StarSpikes filter to emphasize certain stars or constellations. I also use DxO PhotoLab 4 for optic corrections, noise reduction, ClearView filter & smart lighting. And the I have recently started using Luminar AI. I normally pre-process in DxO as just outlined, then open in Luminar AI to use some of my saved templates & with Astro I take blue hour foregrounds & then use the Sky replacement tool in Luminar AI to bring in my edited Milky Way or star photo, taken later that night. I tend to simply prefer a “template” approach to my landscapes & Luminar AI seems to fit that situation nicely, although I also normally do further edits after applying the templates. DxO also provides a “template” environment, which I had used a lot of in the past. DxO also implements the control point methodology for masking, which I found much easier to get on top of than masking in Affinity. But I know in reading reviews & comments of of others on this forum, once you get on top of the masking learning curve, it’s not difficult. I just never seemed to be able to get there.
Additionally each product addresses or doesn’t address digital asset management, so if you just want an editor then the DAM issue isn’t relevant, but once you start down a path with learning an editor it’s difficult to go a different direction, mind you I’m speaking from a “senior “ age with no editing experience until the relative recent past. I know all younger folks could change course with less issues than I would have!
Back to your original question, my limited knowledge with Affinity, supplemented with many reviews indicate Affinity to be a touch notch editor.
Sorry for the long discourse, your son probably could have used each editor out there & made his own decision in shorter time than this took to read!