A suppressor cannot be obtained from the manufacturer- you need to go thru a retailer. Silencer Shop, Esilencer or Capital Armory have posted prices.
Read the Energetic Arms website on titanium vs stainless. Energetic Arms was a company started by engineers to design and make suppressors. Your son will benefit from a 3 oz suppressor.

I have an Oculus I am very satisfied with.

I have a SilncerCo Sparrow on my Ruger American bolt action and a Dead Air Mask on my 22/45 MkIV. I can’t really tell a difference in noise attenuation (yes, I have switched them across the guns to isolate the platform differences) - both are quiet enough that I can use them on my 9 acre property with neighbors about 100 yards away without their calling the cops (we get along and they’d call me first anyway).

The big difference is in dissassembly and cleaning. The Mask is MUCH easier there. I don’t clean the Sparrow much because it is a pain. I’ve actually tried to buy new split halves and chamber section from SilencerCo (the external tube is the serialized suppressor - the innards are replaceable parts) so that I can just swap them every once in a while and drop the dirty parts at my LGS for them to clean but IIRC SilencerCo really didn’t want to sell me those parts for some reason.