Shorest answer... Depends on what's on the media he is playing...
Longer answer...
The 3806 does not decode the HD audio formats if sent as bitstream (as saved on media). But, the 3806 has HDMI v1.1 meaning it can transmit 8 channels (7.1) at 192KHz signal... not sure where in the manual you read the 48KHz limit (I could not find it). Decoding of HD Audio formats is mandated for current gen players but it is not mandated to be output as analog.
Therefore, unencoded audio over HDMI to the 3806 will work. But, if it is about compression vs uncompressed, see below.
"I have too much time and nothing better to do at work" Long answer...
To be sure, the HD audio formats (DD+, Dolby TrueHD, DTSHD Master Audio) are all compressed, albeit, in a losless format. And DD, DTS are also compressed but in a lossy format. Like an FLAC vs MP3 are both compressed. So, they are all compressed regardless or whether in a lossy or lossless formats.
It might be easy to think PCM and LPCM are truly uncompressed, but these days you have CDs that are also compressed... so what gives? We need to start from the source.
The amount of compression depends on the recording master and quality of mastering and conversion to final format on the media.
A monoaural digital recording's quality is (keeping everything else constant) dependent on Dynamic Range and Sampling Rate. Basically, greater range and higher sampling rate yields better recording potential. In the realistic world, this is often refered to in the numbers "16/48 capable" or "Burr Brown 24/192 DACs (digital to analog converters)", etc. on a player or receiver's capability of handling the material. i.e. able to resolve material recorded at 24bit depth at 192KHz sampling rate. REF:
http://www.tweakheadz.com/16_vs_24_bit_audio.htm
(this sounds somewhat Matrix-ish) The true question is where is your digital to analog conversion happening, while how many conversions it takes to get signal to the speaker terminal...
When sending audio to the receiver on the HDMI, the Sony converts the encoded audio to PCM and sends it to the receiver. Now the receiver can appy any processing (like Audessy Corrections or surround mode settings), convert to analog, amplify and send to speaker outs.
But, when using the 7.1 input on the 3806, the Sony does still does the decoding to PCM, then further converts to analog and sends the analog signal to the "analog pre-amp" on the receiver. Now the receiver will convert this signal to digital, apply any processing and reconvert to analog. Then amplify and send to speaker outs. Phew... (unless using Pure Direct, in which case only amplification is done)
This is why folks look into the DACs (digital to analog converters) on a player/ receiver and try to have the better one perform all the processing and in the larger picture, try to keep processing steps to a minimum.
Eg.
My Denon 3910 has superior DACs than the 3806. Therefore, I perform all audio processing here, and send analog to the receiver's 7.1 inputs and run it with the receiver on Pure Direct.
But my PS3 is connected via HDMI since I do not have a choice as to where I want to have the decoding done, and Audessy is applied since only one DAC is exercised).
So is syour friend getting uncompressed audio?
Playing a the HD Audio via analog on Pure Direct will come pretty close. But then you get no video or Audessy processing. And it is well known that room response has a much larger impact on sound quality (in the realistic world listening scenario) and therefore what is the tradeoff?
Excellent theoretical sound vs not so excellent real world sound...
Personally, I am hard pressed to tell the differenct, though any audio sounds better throught the PS3 when played over the 3910. So maybe the Audessy is doing magic and making the sound more accurate than having a less processed signal.