How to mention a recently dead scientist?
I would strongly advise you against that idea. A well written article has to remain objective. Your relationship with that scientist is not a matter of any importance in the research you are describing in the article. Even adding qualifiers to the name is a bad move in my opinion, as you would be imposing your judgement to the reader. 

I know this might seem a nice gesture in the moment, but the article is here to (hopefully) stay, and this type of personal/temporal address will become even more irrelevant to the reader.