Graduation is a great symbol in your dreams even if someone else is graduating. It signifies achieving a spiritual milestone or spiritual goal in life. Your higher self and your guides celebrate these events as they are so important to your development. In terms of spiritual development it is generally the sequence of events that is significant rather than the timing so each goal achieved means the next one can now be focused on.
Graduating in a dream can also indicate you are a guide - you've already learned all the lessons the physical dimension has to offer and are here to use your abilities to help others.
Seeing someone else graduate lets you know their high level (they are a guide) but it also means this is within your grasp as you have sight of it.