I am so sorry to hear of your loss. It is so hard to face the death of a family member, especially when it is "out of time". My thoughts are with you.

As for your dog....The relationship between you and the dog would have to be very poor indeed for your dog to not notice! This is obviously not the case as you have noticed the change in behaviour. We don't realise how many signals we give our dogs all the time about the mood we are in, what we are feeling, if we are feeling unwell ( the dog will often know before you do!), if we are hungry, etc. etc. Your dog will certainly pick up on your emotional state and know how you are feeling - it's one of the main reasons dog ownership has survived past the "we kept dogs because they helped to feed us" phase. They are not called man's best friend for nothing. Accept the empathy your dog offers, and the comfort - you are not imagining it.