not sure I should read too much into him telling me mirrorless is the only way forward now.
For the manufacturers, mirrorless is the way forward. Sony, Panasonic and Fujifilm have been been producing mirrorless systems with (relatively) small sensors for several years, and now Canon and Nikon are starting to introduce large-sensor mirrorless systems. In five years or so, all their professional or prosumer cameras will be mirrorless.
For the customer, mirrorless isn't mandatory (yet). It's more important to get a camera that you can use, that you can afford, and that works well.
For the retailer, the way forward is to sell the camera that will net the greatest profit.
The step from Digital SLR to mirrorless is far less revolutionary than that from film to digital was. Nikon's recent announcement of their first (large sensor) mirrorless cameras didn't make all their existing DSLRs obsolete overnight. In fact, they will still be selling DSLRs for years (as they transition from one technology to the other), and the benefits of their mirrorless bodies won't come to fruition properly until they have a broad range of lenses that make use of their new mirrorless mount.
Don't feel that you have to get the latest and greatest. Any DSLR or mirrorless camera manufactured in the last few years will be a perfectly capable camera, and will let you learn about the camera controls and techniques that aren't easily usable on a mobile phone. (Aperture control, focus and metering, tripod work, flash options, etc.) Go for something you can afford, and that you will hopefully enjoy. Having used your new camera for a few years, you'll have a far better idea of wheter you need the added features of a more expensive camera or not.
(I bought a manufacturer-refurbished Nikon over seven years ago, and am still happy with its performance. There's nothing on the market that makes me want to spend money replacing it yet.)