My SO plans to attend an art workshop held in Italy spanning 6 months. The workshop takes 2 full weeks per month. We are not sure about which visa he should apply. The workshop is not held by an registered education institution, so I doubt whether they will accept if he applied for a study visa.
As a sidenote, he is a Hongkonger and he holds a HKSAR passport (but doesn't currently hold, though eligible for, a British National (Overseas) Passport, if this makes a difference).
Which visa should he apply for in this situation?