Medical for non accompanying spouse

[JollyRancher]

Hello,

My brother is in Canada and his spouse is back home. He is applying for his individual PR and spouse is non accompanying at this time. In the PR documents list it asks for spouse and dependant medical exam.

Is the medical exam required upfront?

or later once the officer request for it?

if it is later, then what should be uploaded on this medical required area.

thanks