There are 'jobs' as such assigned to the spirit realm, just as in life.  A spirit guide qualifies for the job and is drawn to an individual on the law of attraction.  This is important because it is a relationship of love and caring from someone who never met you in your earth life but loves your energy.

There are angels beyond this realm of spirit input.  They come when there is a specific problem or need.

Now our loved ones, they are our relationships and special to our memories.  If you would have taken their advice in life, there is no reason not to listen in their death.  

My grandfather was an gambler and all round scoundral according to what I have been told, I hever knew him.  So whether he saw pictures of us or not, we could not  have known.  So why in his death?

The process is to make a very loving friendship with the unseen world.  And this is best accomplished on energy.  Being compatible in any relationship is about our love and attachments.