How long skull fracture heal in child 15 months old?

Depends on the type: Linear, depressed, diastatic or basilar? Some types take 3-6 mos. To heal completely. See http://www.Childrenshospital.Org/clinicalservices/site2020/mainpages2020p4.Html. Traumatic brain injury warrants a referral to your state health division's early intervention program for periodic developmental assessments & any needed therapy. Safety-proof your home to prevent recurrence. Hope all goes well.

Fracture healing: Children heal fractures remarkably quickly. As long as the fracture wasn't complicated (i.e. Markedly comminuted, or open, or infected etc) then it should be almost completely healed within 4 - 6 weeks.