We need to be aware that the times are changing (or have already changed) in which the youngsters tend to seek their share of freedom and liberty in an assertive way. While it surely is important to "discipline" a child, I feel that the traditional way of doing it, especially when the "child" is growing up to become an adolescent, may misfire once in a while. 7 years is an age in today's world for a child to demand conditions to meet his legitimate needs. If we forget it and start thrusting our needs onto him, expect it to bounce back sometimes. The opinion of others that you are becoming too "soft" on him may be coming from a belief system in which the likes and dislikes of the elders dominated the child's upbringing. Things have changed and that is a reality that any sensible person can observe in today's world.
Knowing the mindset of elderly people who still value the traditional ways of "family-centric" childrearing as perfect, I do sympathise with his grandma who is likely to hold on to her belief system, even if she is the most caring and loving grandma. Changing her outlook may not be easy. Hence I find your role in your son's upbringing as one which should balance the child's emotional needs as well as the needs of the people around who want him to grow up in a "disciplined" fashion. If you deal with your son as an individual rather than as the grandson of a respectable family and extended families and maintain transparency with him in an age-appropriate way while dealing with his needs of personal freedom, he will learn to be more accommodative in upholding family values. To get guided more on how to deal with your son (which is more important than his blindly following his family discipline), you may, preferably along with your husband, consult a psychologist.
Next Steps
Please try to seek guidance from a psychologist.