I think so, but so many people disagree with this. They taut bible passages and such, but my personal experiences would tend to make me think that the strange, weird and usually fun activity in my life would be that of my relatives. The main reason I think that is that it is their sense of humor that is the same. Whenever something bizarre happens that I'll attribute to an angel or something a little (not alot) paranormal, I ask myself, "Who would have thought that was fun/funny/meaningful?" And every single time, I can identify which one of my angels would have enjoyed that right along with me. I think this book, Angel On Board is really quite on target. It was fun to read and really fun to appreciate the new level of existence that it gives you a peak into.
Humans who have died are not angels; angels are separate and unique beings created by God. A Spirit of a loved one CAN visit and do various things (help, protect, etc), but an Angel would be SENT by God with a purpose (i.e.: protection) or a message...but they are two different spiritual beings.
You say tomAto - I say tomato. Does it really matter the label if the message gets through? People who are so stressed how Heaven works - first of all - are guessing. Second of all, because of their strong allegiances to these guesses create division in the church, this country and all sorts of places. Stop correcting people. If you find truth in something - look for what to agree with, not what to argue with.