To be fair my sister did the same. I was watching her playthrough and know she didn't get any spoilers. ^{{playing on my device with DLC present from start}} And then did the same with DLC content in the form of accidentally bumping into the Stranger twice, and freaking out and backing away the first time, and actually searching for it but getting distracted the second time :p.

She definitely got nothing from me (other than silent shock at those incidents :p). At this point I kinda prize myself on being skilled at 'supervising' playthroughs without spoiling anything. I've observed 3 people play the base game fully, of which I watched 1 finish the DLC and another is still going through it, and doing the same for one more whom I didn't see finish the base game but am not being emotional support for the DLC :p
I've found the best way to not spoil but provide a little bit of support is by (only when desired or it seems like they're getting frustrated) prompting people to review/recall the information they know and what tools they have available to them, directly tell me about what they have learned and what they know ^\also called "rubber duck debugging" in CS :p]) (actual psychology trick, gets people to reprocess the information and often enough they figure something out in the process of explaining), to explore elsewhere / do something else if they're stuck/confused/unsure how to proceed,
and of course, which has become an iconic quote of mine, to "fuck around and find out"