I find it surprising he has recommended no upper body work at all until next year - as for me this could even create more imbalances and possible injuries when you do return to upper body work after such a long lay off...
Surprised they have not suggested even some light bodyweight exercises, band work, light cable work etc - even after a month or 2 of doing your pre/re-hab exercises...
Your injure must be fairly bad for him not to suggest any gym work (Upper Body) for 5 months.