I think your fella needs to go down the Citizen's Advice and get some (advice)
Clearly there are things that you dont know -and a few other things that keith (your friend) doesnt know
Are they paying him ? If they are they can do what they like really.
when it comes to a disciplinary, the firm has to follow its own disciplinary code - which a small firm may not have - and the Rules of natural justice. They only thing is, that if it is a small firm, then separation of powers (different investigator, different judge, and jury may all merge into one)
If they are gonna hold a disciplinary, then he must have been told what the charges are - although perhaps not actually see the letter of complaint.
Keith needs advice.
Summary dismissal - dishoneaty - stealing - drunk while at work, fighting.....I mean he should actually remember something like that .
I wonder if someone has alleged he has been stealing