Alex is Griffin's best friend and the one person he trust with complete confidence. If Alex has an idea or suggestion, Griffin was always hear him out and will always take his suggestions seriously, even he does not personally agree with them. The two also have similar taste in movies and, to some extent, music, making their friendship even more solid. He is rather protective of him since he is like a brother to Griffin but he also gives him room to develop and is not afraid to let him get knocked around a little.
At first, Griffin thought Michelle was very strange since she did not know many earth customs or axioms. Regardless, Griffin found her very intriguing in this respect and easily began to forge a strong friendship with her. After seeing her put her life on the line for, not only him but his friends and city, he began to develop stronger feelings for her that stretched beyond simple friendship. He initially hid these feelings from her, however, fearing that they would ruin their recently created friendship. He did not reveal them to her until she confessed her feelings for him, causing him to finally tell her the real truth.
Griffin and Kalil do not seem to get along that well and always seem to be fighting or bickering, much like actually brothers. Kalil seems to show a lot of animosity towards Griffin because Griffin hurt Michelle when he lied about being in love with her. Since then, he has been showing an increased level of animosity and does not show signs of changing this any time soon.