Is the Pentax AF lens compatible with Pentax K-mount camera like Pentax K1000 even if the autofocus dosnt work

Yes, provided that it is not a new lens designed for use with Pentax DSLRs. All Pentax lenses are usable (with that exception), even including old screw mount lenses (with adaptors). Pentax has always kept faith with its customers.

provided they both have the compatible bayonet mounting it will be ok. you just wont ave the AF function to use.

According to my understanding, all Pentax lenses are interchangable between cameras. If it's not, there are adapters you can purchase to make the lense fit the camera.