Yes it can. It is my experience, too. Sometimes communications is very clear; hearing full sentences without any doubt of what was said. Other times it is another type of communication thoughts but not words - understanding more like.
For me, my father was very present when my daughter was little. My grandmother has helped me, my late brother shows up from time to time - mostly to help me not be so serious
And I've been visited by a man who committed suicide who was rather lost. And by a good friend as a last goodbye.
Who knows if this is 'real'. There can never be any proof of it. No one can ever 'hear' inside my head. To me, my acceptance of this phenomenon, has been gradual, from fearstricken terror as a young child, to just shaking my head 'I don't believe in ghosts, I just experience them' - to today, where these meetings are part of life, bringing support, advice and care. No big deal, just great loving friends.
Don't worry if the experience starts to fade, it can slow down a bit, and then come back. And either way, they will always be there, whether we hear them or not. Good luck.
And I am so sorry for your loss <3