I mean this as kindly as possibly, but I would have a serious think about what kind of life you’d be inflicting on a second child.
A newborn whose mother can’t be physically and emotionally present due to the needs of your first child. With the rest of their childhood potentially being the same?
Living in a home where they may be scared for the their safety? A home that is full of stress, anxiety and difficulty?
Being forced into a position where he has to be a young carer to his brother? How can that possibly be avoided when his bother has 24/7 needs? In lots of ways he’ll be drawn into helping you.
Will he have grow up with his own needs always coming second in line to his brother albeit nobody’s fault?
Potentially being a carer when he’s an adult?
Think about the potential emotional damage you may cause a second child having to be bought up in this kind of environment, both short term and long term.
Realistically, how can you provide an enriching and fulfilling life to a second child when your first child is physically aggressive and has 24/7 needs?
How do you envision a second child fitting into your life without there being any kind of detrimental affect to the emotional well-being of either child?
Having two children is hard….the physical and emotional toll it can take is huge, trying to meet both their needs equally and make them feel equally important and equally loved etc, and that’s just in a situation where both children are well and healthy.
I think you need to have a serious think about how you will cope because once baby number 2 is here there is no going back.
I don’t see how having a second child will be fair to the child you currently have, or fair to the child you will be bringing into your home environment and the kind of life they will have no option but to be part of and the impact it will have on them for all of their life.