I bet he thinks he's an adjuster.
Adjusters interpret and apply policies, they don't look at damaged cars. Estimators do that, they're usually retired mechanics or bodyshop techs that do it part time.
PROPERTY adjusters will go out and view damaged houses and sometimes estimate the cost to repair, but not auto. Either he legitimately was an adjuster, in which case he doesn't know how to estimate for auto damage, or he was an estimatics guy and doesn't know shit about policy wording.
If you drive a shitbox that's worse next to nothing, don't bother with comp/collision, it's a waste of money. If it's a decent car, you'll get a good ACV settlement to buy another car/put towards another purchase. There's really no benefit to the insurance company, they just determine which option is less expensive (fixing or writing it off and giving you bluebook value).
Keep in mind that as adjusters, we have zero inventive to try and fuck someone over. It's not our money, and we're bound by the policy allowances. I like helping people out where I can, but a lot of the time it's just not up to us, the contracts are pretty iron clad.