Phillip is angry because he is grieving the loss of his eyesight and his lifestyle as he knows it all at once. Anger is one of the steps that people take when they grieve a great loss. He is angry at his mother because he feels she has left him on this island with Timothy who is black. Phillip has grown up thinking that color means something when it comes to who a person is and he is angry to be stuck with someone he feels is beneath him. He is scared as well and it is being projected as anger, ungratefulness, and entitlement. Phillip goes through the grieving process for his eyesight and eventually comes to accept the loss and learns to live quite successfully with his blindness. He also learns a great lesson about friendship and tolerance. Phillip had to become literally blind to overcome his misconceptions of people who were different.
If it wasn't for Phillips mom, he wouldn't be on that raft with Timothy
because he thought it was their fault
He was mad at Timothy for pulling him onto the raft and mad at his mom for leaving Curaco and go on the boat.