You better report the PM to the mod as unsolicited PM. Also a confirmation from he mod who will handle the report will ensure that your evidences are true.
However honestly speaking, I do not think anyone is going to tag this user just because he asked some smerit. There used to be time when it was very sensitive but these days especially after introducing the trust flag the tagging culture changed a bit. One can leave a neutral if they are satisfied with the evidences but for me I will pass it until I see a confirmation from a mod or a highly reputed user.
edit:
To prove my point,
the feedback left by Vod is from 2018 which was the early stage of introducing merit system.