Travelers (and locals) are not able to purchase Cannabis items that contains THC in Germany, and this would possibly not adjust. You can not lawfully take weed from a German community who is increasing it for their private use in the home. This could criminalize you and him. I.e., https://buy-cannabis-in-germany01345.buyoutblog.com/36380057/new-step-by-step-map-for-buy-cannabis-in-germany