Thank you for your query.
I will not worry about the green stool
as long as they are not watery.
Yes, it is time you started solids for your child. Kindly start by giving him liquid to semi-solid food and gradually going to solids. You can start with soups, fruit juices, mashed potatoes, mashed banana, etc. Gradually increase the consistency of the food so that the child starts using his gums.
I hope I have answered your query to your satisfaction.
Wishing your son an early recovery.
Rajiv K Khandelwal