How to deal with unwanted physical contact, presents and attention by a postdoc supervisor? Posting this to academia stackexchange, but if this may fit better in other place please let me know.
My girlfriend is a new PhD student in a male dominated field, and is supervised by a postdoc in a research group led by a professor. For the last few months, her postdoc supervisor was constantly giving her small presents, and trying to meet with her outside of work hours such as in a restaurant on weekends, for a reason of discussing the current work. This makes my girlfriend uncomfortable, but she is too shy to say no to those things, and the behavior of the postdoc supervisor up to this point was borderline, I even accompanied her for one such meeting on a weekend. Yesterday however her postdoc supervisor surprised her where he took off her glasses from her head without her asking or warning her (because her glasses were a bit dirty); My girlfriend was startled, and pulled the glasses from his hands, and put them back on. At this point he further unannounced tried to touch and fix her hair, as she put her glasses in a rush which messed her hair. The overall situation stressed my girlfriend considerably, and she ended up in tears in the evening when she was telling me this. There have been some other similar situations (albeit with no / less physical contact) which makes my girlfriend distracted and nervous when she communicates with her supervisor, which impacts her ability to do her work.
My view on this is that we should let her supervisor know clearly that this behavior is not acceptable asap and escalate to the professor, in order to prevent such situations from happening again. The issue right now however is that her scientific work is depending on her supervisor, so she does not want to escalate or bring up this situation for discussion until the paper deadline that she works on. I am inclined to go and talk with the professor and postdoc myself, but I also do not want to do anything that my girlfriend did not ask for. Do you have any advice for me of what I can do to help? Do you have any suggestions or comment in general what to do in this situation?
Edit 1: As pointed in the answers / comments, I will not attempt any talking with prof or with postdoc on my own or other similar actions.
Edit 2: Unfortunately some 1:1 situations cannot be avoided, as my gf needs to take measurements together with her postdoc who knows how to operate the machinery.
This might be more of a Interpersonal Skills question, but:

don't take any action on your own
do support your GF in any way she asks, including (1) being supportive and helping her deal with the stress (2) being present as a third party at meetings or (3) in conversation as a reminder that she's unavailable or (4) as an excuse (&quot;oh, sorry, I have plans with my boyfriend (cough) so it'll be inconvenient to meet in person this weekend, but we could communicate via Zoom/Slack/e-mail ...&quot;) — not that it's OK that any of these are necessary in the situation.
after the submission deadline passes, it's a judgement call (depending on personalities, relationships, etc.) whether it's best for her to try to work things out with the postdoc supervisor or go immediately to the professor

@Buffy correctly points out in a comment (I should have included this) that the highest priority is for your GF to stay safe by making sure never to be in a private/one-on-one meeting with the postdoc: if you're not available or she doesn't want you there and she can't set the meeting for a public professional space, ask her to ask a friend or colleague (especially female) to be there (mentioning this advice to your GF would be the one possible exception to &quot;don't give her any help she doesn't want&quot;). If your GF and the postdoc need to work together to take measurements on some equipment, do whatever you have/she has to to make sure there's a third person present.