No offense, but as a channel with about 100 subscribers, it's VERY unlikely someone is purposefully copying you. People copy others to try and get the same success, which isn't all that apparent yet. Posting on the same days could easily be coincidence, and I'm not sure what you mean with "signing off." If it's like a very detailed closing message, then he could very well be copying, but something like "peace out" or similar could also be coincidence.
Why do I care so much?
A guy in the same niche, much smaller than I am was accusing me of copying him, starting drama in the comments section of my videos, etc... It really p****d me off especially because I never even watched this guy's videos.