I am so sorry...I was enmeshed with my alcoholic mom and I felt that Dad, who was ill his last 11 years expected me to take care of her...and I did a lot of caretaking his last 11 years to 'help' him and her...and with her...when he could not.
She wanted others to do so and it ended up causing me a medical diagnosis of trauma...but I am so glad I worked through it...was not as aware as you are at the time...and I just knew I had to work on me...and I continue to do so.
Your son has a chance and you can make it real for him as his mother.