Ego practically means Esteem Gets Offended. Normally people who are strong and have depth of life, are down to earth and respect the feelings of everyone around. But a weak boss always has a high ego. Though he has an inferiority complex but behaves superior to cover up his shortcomings.
While managing a boss with high ego, you must remember that he must be given a feeling that he has the required wisdom on the subject. The rule is, never to attack his ego by challenging his knowledge BUT instead share with him 3-5 options focused towards the solution of the current problem or management of the current project. Share all the pros and the cons with the relevant logic. And seek his opinion. I repeat – seek his opinion.
Let him have the feeling that it is his idea only. This way you have saved him from the embarrassment by giving him a feeling that he knows the subject well. As a result he will feel more regard for your presence in his life and will have the priority focus to maintain his relationship with you.