Focusrite Scarlett 2i2 4th Gen USB Audio Interface for Recording, Songwriting, Streaming and Podcasting — High-Fidelity, Studio Quality Recording, and All the Software You Need to Record

arturia Keylab 88 mk3 is a very good controller keyboard with traditional piano feel keys. It comes with great softsynths and it will work very well with the ableton 12 which he already has. It costs more than $1000 though.Now if he has an electric piano which has a din plug or even usb plug for midi then you could even skip the controller and he can use his piano to control softsynths or if it is a din output (see picture in another reply you got) a synth module without keys.For very reasonable money there is the arturia keylab 88 mk3 essential, which has more basic synth keys but comes with a similar software suite.https://www.amazon.com/Arturia-KeyLab-Essential-88-mk3/dp/B0CV9J11TZ/That would leave money for a sound interface for his computer, such as a good and reasonable focusrite scarlett 2i2:https://www.amazon.com/FocusriteScarlett2i24th-Interface-Songwriting-Podcasting-High-Fidelity/dp/B0C5JRTS3Y/Then he also needs monitor speakers, they can be connected seamlessly to the scarlett. Which could be part of the present or he can get them later. JBL makes pretty decent monitor speakers for a budget, for example the 305 (306 and 308 are bigger), you need a pair:https://www.amazon.com/JBL-Professional-Next-Generation-Powered-305PMKII/dp/B077N2GQXC/