* Show more interests by asking questions on the kind of person which more likely to cause an offence at the person with the invisible difficulties expense.
Also ask more on the kind of location and the time of the day. This is important to build a picture of what they are experiencing.
* If you notice they are uneasy, upset or emotionally never tell them off or make any lectures on their cope & respond at any level.
This is because you are making them feel that using their difficulties as blame on something is not their fault & you are humiliating them & embarrassment. In addition of the bully or the offender may notice if the affected is seen being told off will see their tactics as successful to make it out the effect is a blame. They see is as they have won and as an encouragement to escalate the abuse further.
* Additional questions you could ask to show more interest could include
"What do you think which makes them do this?",
"what similar things have happened which leads to this?" and
"how this is affecting you?"
* Offer some suggestions but accept they might disagree if they think it will not be helpful for them.
* Offer help the next time this occurs again.
* If this occurs never communicate which cause a situation to cause that person further upset or to make them feel you're not helping.
This including not telling off attitudes or to accuse them if not listening or to make remarks such as matter like "you should strategise better". Remember just like you they also have dignity & their rights to choose, to accept or reject what's important to them.