i agree jcrowfoot. spirits of the dead usually manifest in the dreams to remind us, say hello or warn us from unprecedented events that might occur. better that way...
you'll know if it is really a dream or spirit manifestation if you feel strange when you wake up such as in your case, you feel the same thing as your in-laws. just listen and take note of what they are saying and relate it later to your activities and you'll know why
real dream about dead relatives on the other hand only signifies our desire to be with them at least in dream as for its meaning, it will depend upon whether we dream of them as if they were still alive or we knew from the very start (in the dream of course) that they are already dead! if it is a ghost in your dream, there will be a new business opportunity for you or your love one (your husband?)
If you haven't the strength to impose your own terms upon life, you must accept the terms it offers you. - TS Elliot