Hello everyone.
Just received a bamboo plant from a friend. It is in bad condition, yellowing a lot. I am keeping it inside under a grow light for now as it is cold outside and this bamboo plant has been kept strictly inside as far as I know. I plan to put it outside in the spring when it warms up a bit. I suspect it is also rootbound as it is potted in this weird stiff rock mixture in a very small pot. I don't know how to describe it but when I first saw the bamboo I thought it was fake because the rocks were so packed together and unmovable that I assumed no plant could grow in that.
Has anyone had a similar problem? How can I revive this bamboo? Should I try to repot it and risk damaging the roots? How do I remove the rocks? I've never dealt with bamboo before and any advice on how to proceed would be much appreciated.
I can post a picture if needed.

You know this is a bonsai forum right?

It all depends on what species it is. Without that information nobody can help you. If you post a picture and species here, someone may be able to help you. But if you post it to a gardening forum the chanse of quality answers is higher.