Well there are'nt any good family hotels at Khuzdar.
I stayed one night at Khuzdar FC Cantt No. 4 last month as I got some reference in the army.
I suggest you to approach the watchmen / guard of DC Guest house (it is located on the main Khuzadr Road, opposite to PSO Petrol Pump) and you can offer him 2000 to 3000 for a night stay at DC guest house which is very clean and ideal place for a night stay.