Depends on what you mean with “good with Spotify”. It plays tracks from Spotify, has a matching the playing track feature that can be handy in finding some new combinations. Not sure if the app does off-line Spotify tracks though.
As for controllers, the one that I found very pleasant was the Numark iDJ Pro. The iPad sits inside of the unit making use of the touch screen very easy. All that is missing imho is the channel faders, you get rotary volume for the channels.
Other options would be the Reloop BeatPad 2 and DDJ-Wego 3. All the other options are too far away from being a “standard” controller lay-out that I would not suggest them.
Should your friend ever decide to play out with his setup, be sure to tell him that it is illegal to play from Spotify for an audience/in public.
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