My dd has had NTs, (knock wood, not for over a year now!)....OT was a contributing factor, as was OS or a big change (the start of school, for example). Her being hot was a trigger also, so make sure his room is cool and that he isn't overdressed for bed.
NTs would be kind of unusual in a one-year old, (certainly not unheard of though), but the triggers can often be the same. I would absolutely try W2S to see if that works!
The good news is that they don't remember NTs, and as hard as they are to witness (my dd would sob and beg me to please go find her Mommy
, she also has gotten out of bed and knocked things off her dresser...awful.), the child isn't in any danger. You're supposed to stand back and do nothing, but I could never do that....I would just repeat to her "You're safe, you're ok. You're safe....". UGH.
They also run in families.....any sleepwalkers or NTs in you or dh's past? In our case my sister and brothers kids had them as well.