Hmm, those canines/2y molars can be pretty brutal though, they bothered my DD a lot at night whereas previous teeth never had. Both came with very difficult bedtime settles too, but obviously you are there and know if that's not the case for you
. May be worth a one-off try of meds to see if it makes a difference? Separation anxiety can flare up at any point really, half birthdays are prime time for sleep silliness and developmental changes.
How are you settling him?