If I were him I would look for another insurance broker. I have a close friend who rents a PA23-180 (Apache-Geronimo) for about the same price in central florida for instruction and solo rentals and does not have this restriction. His insurance requires 50hrs multi or 20hrs in type for solo.
Like previously mentioned the Apache is a great airplane but is different then other trainers such as the seminole. It actually has a legitimate critical engine and only has 1 engine driven hydraulic pump on the left operating your flaps and gear. This airplane can quickly turn into a handful for a low time multi pilot. For this reason it is a great multi trainer in my opinion and will make the transition to 135 gigs operating Aztecs or Navajos very easy.
Outlaw: If your friend is interested PM me and I will forward you the contact information of this insurance broker if he feels this restriction is hurting his business.