Recent tweets include one about a person getting bitcoin-shaped chocolates from his wife, and I highly doubt anyone paid him for that.

Checking Darcrus twitter (https://twitter.com/darcrus), all I see related is 2 tweets about Coinigy.  He might just be doing so because he likes the service.  (In fact, it does appear kind of interesting; I will look into it).

So I wouldn't worry.

The minor and casual tweets are good in a way, as they remind everyone he is still around.  That is better than some developers on other projects, who just disappear for weeks.