Are the reduced-intensity high beams not enough? I believe that's what the 2015 uses for DRLs here in the US...
Should be if that's what is used. My 2018 has LEDs around the outside of the lens.
I lived in the UK for a few years and while you never think about it, there are key differences in the cars due to region specific specs.
Also note that at least on my Canadian 2018 the headlights are Euro headlight pattern (a sharp cut in the projection with a definite end to the light vs the fuzzy fade-away pattern US lights have). Those are legal here as are the US headlight patterns. I am not sure if his car would have the Euro headlights or not, but I have heard of some US cars needing to replace with Euro lenses.
And of course, if the car is going to Britain, LHD is legal but the headlights HAVE to be replaced for driving on the left.
Bumpers are also potential issues as American collision standards are designed for car-to-car where Euro bumper standards are more to protect Pedestrians. This may be a needed modification.
Plus, the radio won't likely work properly, as Euro radios rely on RMS technology that is different than the US and do not just have odd decimals on FM stations.
Licence plates are not the same size although some countries have square ones to fit on US and Japanese spec imports.
Euro airbag, seatbelt and crash test standards are also way more stringent, but generally a personal import is exempt from that.
So, in a nutshell, sell the car and buy a new one over there.