Dont try reasoning - it doesnt work as logic and reasoning is one of the first things to go. Reasoning with him is likely to just make him aggressive. Bits of newspaper "hidden away" is annoying, but IMO doesnt do any harm and best just ignored and tidied up when hes not there. Unless the behaviour is anti-social, unhealthy, or downright dangerous Id leave him to it.
All very well, until the person is going mad trying to find whatever they've hidden, and blaming everyone else for hiding or taking it.
I well remember a very long hunt for something FIL had hidden - probably his defunct bank books since he was obsessed with them. He was yelling, 'I - go -crazy!' with fury and frustration, and after so long searching until well past all our bedtimes, I flipped and yelled back, 'We're going bloody well crazy, too!!'
Forget where we eventually found them - probably in or behind books - a favourite hiding place - and we have an awful lot of books on an awful lot of shelves in this house.
When he went to stay with BIL and SIL for a few days, they eventually took away the bank books he had been so obsessed with - he kept them in an old tartan shopping bag and was constantly taking them out or worrying where the bag was. Driven mad, they took the whole lot away and told him it was gone.
At the time I thought it verging on cruelty to take his 'precious' bag away, but in fact he forgot it completely within a very few days. And I must say it was a relief to have an end to the constant fretting and obsessing.