Don't mean to be harsh to the CFII here, but this is IFR Instruction 101. It's 100% relevant to the task at hand of training an instrument pilot and preparing them for the checkride. I'd be concerned, although not quite ready to pull the plug. Ask them for clarification on LOGGING vs ACTING as PIC. If that doesn't jog their memory or spur them into action (ie, check FAR references), then I'd be legit concerned.
We're not talking about places where you can do aerobatics, O2 limitations for crew vs pax on a Part 91 flight or parachute packing requirements....we're talking about logging IMC time during your instrument training! If he/she isn't well-versed in this reg, then there's a good chance that other regs of a similar nature or not well-understood either (15 hours with a CFII doesn't have to be in an airplane, for example, or ability to log IMC time with an instrument-rated PIC who is not a CFII, etc)
These are not new issues/questions in the industry. I'm not a CFI (not even close) and I have a reasonable grip on these things. When I don't, I know where to go and double check. Your CFI should have more of a grip on these things than an ASEL IR PPL.
For those who would defend the CFII, saying that they can't know everything, I agree. However, this is not an obscure, infrequently-encountered scenario.