I don't think he is a good person, if the term could even describe somebody.
While it seems that he genuinely wants to help Rick in the fight against Negan he assumingly does it only for his own benefit.
Nobody forced him to ambush Daryl and Denise and later tell Negan about Rick and his group so that the Saviors can block all roads.
He also enjoyed taking Rosita's gun and hat and sending her out to find Daryl's bike. He did it when nobody was looking.
Also setting up Carson and having him burnt alive was not the doing of a kind person but simply throwing others under the bus to save his own butt.

He may be of help now because Negan abused him and is still a threat to Sherry, but I can't see that he is a decent or good person. Selfish would fit.

 

No way should they trust that guy. I think he is playing both sides. If he wanted Negan dead, nobody has had better chances to kill him than Dwight. He thought of a plan to save Sherry and take the heat off his own ass. So he should be able to come up with a way to kill Negan and get away with it. But we know Rick will go right ahead and trust him.