MLS-12D
Just to update you - I did as most of the posters have suggested. Tried to be supportive and made indirect suggestions but he won't take the hint. He is legimitately flying solo and remains current according to club rules, so we have 18 months before his next flight with an instructor.
It's been a real eye-opener to me that someone, I thought was a good and safe pilot, is simply unable to see when things are going wrong.
It does make me realise that the implementation of the 2 year requirement to fly with an instructor has great merit. I didn't think so before.