I am a CFI, but not instrument current. I went flying today in IMC with an instrument rated and current private pilot friend of mine. We took turns flying, any other day we would either just split the time or call it an instruction flight and both take all the time and log his time as dual given.
Be carefull now, you can only log dual given/dual received if you have actually taught something.
Going funflying with a pilot friend does not constitute "dual given".
What are you teaching him anyway if he is already PPL/IR rated?
Back to your original question:
You cannot act as PIC under IFR if you do not meet the currency requirements.
You can however log PIC as the sole manipulator of the controls.
My
interpretation is that you CAN log the IMC time and you CAN log the approach under the "sole manipulator" of the controls rule but your friend cannot log that time.
My source:
http://www.faa.gov/about/office_org/...011/Walker.pdf
You may want to do some additional research yourself by searching on the applicable reg numbers such as 61.57;
Regulations Division - Legal Interpretations & Chief Counsel's Opinions