Vortex Sound Research

Hey guys - my son is 15 yo and plays our piano a lot. He can't really read music but he can play some music by ear. He enjoys it and I want to encourage more music-making for him. I was thinking to get him a drum machine but then I saw machines with keyboards built in. He isn't patient so him being older won't make him more disciplined with new tech but I wanted something semi-easy to use and wanted to perspective if I should look for a synth with a keyboard and drum machine or look to keep them separate. I don't want to do the iPad thing or the laptop thing to start. He needs tactile interaction to make the music. Any suggestions are GREATLY appreciated!