Dropping around 65 is healthy for veileds and panthers, unless a chameleon/reptile is sick then night time drops is good for most species. I even allow my leos to drop a bit at night. It's natural and normal. Give him access to complete shade in temps that high (during day time sunbathing) , especially if they are air temps. I always give my chams the ability to go in complete shade on their own. Though my panther often sunbathes all day, during 85+ days he will often blanch and then move into the shade.