“Can’t you just be happy for me?” People say that while arguing involvement in a matter. However, in order to be happy for someone we must be comfortable with their choice. Otherwise it will be our support of that which violates the conscience. Being happy for someone, should cause us to look at the matter and see if any law is broken. For example, why be happy for a person who didn’t get caught cheating on his taxes? Why be happy for a daughter who is going to move in with her loser boyfriend who can’t hold a job and has a drinking and drug problem?
You see that people can be involved in the wrong things while asking others to be happy for them. But godly people cannot honor such requests. 1 Timothy 5:20-22.
So yes, we can be happy for a person as long as there is no encouragement of poor choices.