Chosen Solution
I inherited my sons iPhone 5s, I put a new SIM card in which is ok but I don’t know the passcode. How do I reset it? I don’t know if I can do this via iTunes but I don’t have my sons computer/device. I have an iPad as well as an iPhone 6s Plus as well as the cables. Please help.
Have you tried any of the steps that apple recommends? https://support.apple.com/en-us/HT204306
iPhone is disabled connect to iTunes