Hi guys I have lately been modding quite a bit and for some of my armors I had to use a mod authors mod for his model and textures and so I sent him a message about getting permission and I waited for almost three weeks but I found out he hasn't been on his Nexus profile since may last year what should I do.

Probably shouldn't release anything using components of his mods unless you manage to get permission. Check the Readme files/descriptions for permissions as well, sometimes they'll say things like "You can use these in your own works, just give permission" etc etc.