I have some trouble understanding the conditions of a ticket a friend bought:
- SAVER ticket on both legs (not refundable, not changeable)
- BRU > HAN > BRU

Now, my friend wants to stay in DXB on his return flight, willing to pay a one-way ticket to BRU a few days later. The idea is that we check in in HAN and ask luggage to be delivered in DXB only.

However... I understand if we just leave the airport in DXB and "forget" about the connecting flight to BRU, the no-show fee will be applicable. My ticket (DXB > HAN > DXB) clearly states a no show fee of 600 AED. My friend's ticket mentions that the ticket is not refundable in case of no-show but doesn't say anything about no show fees...

So, if we check in HAN only to DXB and we call EK upon arrival in EK and inform them my friend will miss his connection, will they proactively cancel the DXB-BRU flight thus avoiding the no show fee?

A no show fee isn't really an additional fee the airline charges you but rather a penalty they apply to the value of the flight coupon that was unused. E.g. if you had a coupon (i.e. ticket) for a flight that you paid AED900 for (+ tax) the airline would now charge you a no show fee (AED600) + cancellation fee (AED X) if you wanted a refund, and your refund woul dbe AED900(+tax) - AED 600 - AED X (in reality thus, mostly AED 0). You might get some taxes back. If you decide to call the airline and rebook your ticket they'd ask you to pay fare difference + change fee + no show fee.

Since your friend's ticket is non-refundable he will by default not have a no show fee as his entire coupon value is effectively the no show fee (i.e. he gets nothing back if he doesn't show up).

That may be more difficult than you imagine. Short checking is not allowed by some airlines, although I'm not sure about EK's policy.

This is the real hangup. If you can travel with carry-on only you're fine but don't expect EK to short-check your luggage. It may be cheaper to refare the ticket even if it states non-changeable (you might get lucky).

Have done this before @ DXB. Did not have any issues asking for bags to be tagged only to to DXB from the UK (the ticket was the return part of a ticket DEL-DXB-LGW-DXB-DEL).

The 'stopover' @ DXB was 15 or 16 hours long which might have helped in my case.

The reason that I had to do so was because of ticketing restrictions I couldn't extend my ticket (wanted to stay in Dubai for longer than originally planned.). I flew to India on another airline.

Same here. They asked if I wanted to pick my bags up at DXB on my recent 14 hour layover.