Observe his behavior and attitude. A grumpy person may be out of control and prone to violence, so you should carefully observe his behavior and attitude at the beginning of communication in order to determine whether he may pose a threat to you.
Communication builds mutual trust. If you decide to make friends with this boy, then mutual trust between you is very important. Try to communicate with him and let him know what you care about and what kind of friendship you want. If he can understand you and is willing to establish a good relationship with you, then you can become good friends.
Express your views frankly. If his bad temper brings you discomfort and trouble, you should tell him your thoughts frankly and promptly. If he can understand and change his behavior, your friendship will be more stable.
In a word, a person's appearance and temper can't completely determine whether he can make friends with him, but the establishment and maintenance of friendship need mutual trust and understanding. If this boy has other qualities worthy of trust and appreciation, and there is good communication and understanding between you, then it is entirely possible to make friends.