TACAN and DME
 

If a colocated VORTAC station has a notam stating that the TACAN is out of service, does that mean the DME will also be out of service? i.e. is the TACAN DME the same as the VOR DME?

That depends if it's the azimuth part of the TACAN that's u/s, or the DME part, or the whole thing. Co-located requires certain proximity requirements to be met (or they're not considered co-located). If met, then a VOR positioned near enough to a TACAN is co-located with the DME part of the TACAN installation, and can be considered to be a VOR/DME as far as civil flying is concerned.