G.T.
I delivered my 2 kids there, the latest being 10 months ago, with midwives care. Great place to have babies!
What I understood from the midwives is that if asked they can be flexible with the rules to make the patient as comfortable as possible. The limit to this flexibility is the safety of the patient. If they think the room gets too crowded, they will ask some people to leave.
In any case, check with your doctor or the hospital first but I doubt they would allow a child there. The experience of seeing their moms in labor could be traumatic for them (it is for most husbands!), and the entire hospital experience (smells, movements...) can be at best confusing for a child (not mentioning, the need to sleep/eat... depending on the time of the day and the length of labor)
I remember I asked them if they would allow my son (2 years old at that point) to come with me, because we feared a very fast labor and we lived on Mount Auburn, 5 minutes walking from the hospital. All our friends who offered to baby sit him in case of early labor, as well as the baby sitter, needed 30-60 minutes to reach us without traffic.
The nurses told me that my son could come and remain in the corridor with my husband, but wouldn't be allowed in the room. I ended up giving birth past my due date, so my parents were here to take care of him.
Your son is older than my son was, but I would guess the same rule may apply.