I think it would help if you could define what he meant by "acting insane".
*TRIGGER WARNING, SWITCHING DESCRIPTIONS*
I have had some pretty violent switches. When I have been in high crisis, and I mean SERIOUS TRIGGER, I could be compared to one "possessed by the devil". I twitch, spasm, stretch, my head shakes violently, I mutter unintelligible words...sometimes I've been known to stretch my body further than it should...I mean, that could be considered pretty "insane" by someone who knows nothing of DID. Revolving door crisis, with the slightest understanding of what was going on in my head (as this was fairly recently after being dx'd), make for a fertile playground.
But, with a lot of time, and a lot of counselling, reading and work I am managing those episodes a lot better now. they happen infrequently, and my high trigger times, while unpredictable, are far more manageable.
I'll also state this is MY experience, and I can not comment on how common it is.
*END TRIGGER*
So, I ask what his definition of insane is for this reason, if it's serious then you two should be discussing safety plans...not question the sanity of it. Questions can come much later, in that moment what is best is everyone having an idea of what is happening, to the best of their ability, to keep you (and them) safe.
Thanks for listening, hope this helped