Me and my friend lost someone pretty close to us a couple of years ago. They were a lot closer to them than me and they get pretty sad around this time

You're going to have more insight into your relationship with your friend than we will but I'd say just be cognizant of how they're responding to the situation. People handle grief in a variety of ways. Some people close off, some people disassociate and don't really acknowledge it, some people are a wreck. Since you said it happened a few years ago you should have a little bit of an idea I hope.

Maybe do something together that you all three would have done/have done before to commemorate them? Maybe try to turn it into a positive note or celebration instead of feeling sad about them if possible

No long advice here

The best thing u can really do is just be there

If they need something - which they will, they'll give the indication

Just do something nice for them

Dont over think it as long as it comes from the heart it’ll do the trick 🤞

buy them a puppy named after your late friend

Do this if you want them to get even more sad + throw a heavy responsibility in their lap