Isekai Ojisan

Takafumi's uncle wakes after seventeen years in a coma and calmly claims he spent that entire time in a magical world. Takafumi assumes his mind has not recovered until the man demonstrates real magic. His uncle truly returned with supernatural powers and memories full of monsters and adventure, but he also missed nearly two decades of technology, culture, and especially video-game history that matters to him far more than it probably should. The two use magic to make online videos and earn money while the uncle replays his old adventures like living recordings. The most astonishing part of those memories is often not the monsters, but the obvious romantic signals he somehow failed to understand.