Clutch bleeding issues M600

A mate who bought my old M600 has left it sitting since autumn last year and wants to get it going. The whole bike runs well, but he has lost clutch.

He’s tried bleeding it from the bottom and then cracking the banjo. He’s had air out of it at both ends, but says that it is now coming out with no air.

But he says it’s still not working and the bike creeps when fully depressed.

I’ve suggested a full drain and flush.

Can anyone suggest anything else? Do the M600’s have adjustable push rods in the slave?

How can he tell if the seals have gone in the MC?

The clutch pack has less than 1500 miles on it.

He’a not Very experienced in bikes and it’s in Kidderminster. I’m in Surrey.

Cheers