I, too, think it's unlikely that a normal webcam would pick up the right wavelengths of IR. There's near infrared (about 0.8 to 3 μm wavelength) which is pretty much like visible light and can be seen by most webcams if they don't have a special IR-cut filter to remove it. Then there's thermal infrared (round about 10 μm wavelength) which is what objects at around room temperature give off and which thermal imaging cameras detect. The only thing those have in common is that they're shorter wavelength than radio but longer wavelength than the human eye can see. More here: https://edavies.me.uk/2014/08/ir-myth/