I totally get where you're coming from. You appear to mean only well, and oftentimes people can appear to be asking for answers, 'Why is this happening! Why me!' And if they literally do ask for an explanation, then talking about stuff like the three marks of existence might fit.

Otherwise 'friends who were going through tough times' most of all don't want to feel like they're going through them alone. When I have a hard time, often I already know about its 'ultimate' nature. It's the connection that matters during times like that though. If the other person doesn't acknowledge or reflect-back through their words, then I don't feel like they were listening. It can be as simple as this, 'Wow, what I see is this, I'm here with you and remember you've got a friend in this.' That doesn't even mean anything 'wise' but it happens to be what most people really want to hear when they are in the dumps.

The consoling person doesn't have to have a bit of 'wisdom' to add, often, they just need to say 'Wow, I...don't even know what to say, but I'm glad you told me and I'm right here with you.' That can be a hundred times more sensitive and appropriate than running the risk of looking like you are minimizing the other person's problems by saying 'it's just impermanent.' Minimizing is like the parent who 'consoles' their child by saying 'OK so you broke-up, it's just a girl!' The child knows what their significat-other is, and often isn't asking for answers as much as a 'fan of them.'

I must admit, I didn't know this for about twenty plus years. Before then, I just saw every sad person as a person who needed answers or the proper set of questions that might lead them to the solution. But I've learned that another person often knows the facts and the questions already and can feel condescended-to if they get unrequested lessons; they wants us to process with them the reality that has just crashed into their lives. It's a privilege to be asked to keep company with someone in a vulnerable time, but it's also super hard to know where the line is between 'letting them process' and between letting them suffer needlessly without the right answers (like the fact of impermanence!).