Hi!
I can understand your concerns. It is important to distinguish whether this staring at feet is a ritualistic compulsive behavior or an obsessive compulsive behavior or disorder (OCD). In ritualistic compulsive behavior, the behavior first starts at around 18 months to 2 years of age and peaks at 2-3 years of age. Thereafter this behavior dies its own death. However, an OCD persists and requires treatment. It is difficult to diagnose this on net. To begin with please consult his pediatrician. Engage your child in other activities he loves to divert his attention away from your feet. Please discuss with his doctor. Take care!
The medical advice given should not be considered a substitute for medical care provided by a doctor who can examine you. The advice may not be completely correct for you as the doctor cannot examine you and does not know your complete medical history. Hence this reply to your post should only be considered as a guiding line and you must consult your doctor at the earliest for your medical problem.