Query i need help with

I was recently agreed with a runescape skilling training to do some skilling work on my account. I gave him access to my main account and he later asked if i would be willing to share the account with him and he would get me a discount on the price. He also told me he was not going to be training the account for a bit as it would be his little brother who would be training it. I left 6m worth of supplies on the account and he told me that he was going to take a break from training and go staking with them.

Are these actions reasonable grounds for me to report him?

 

So he took the 6M from the account and used that to go staking? If that's the case, that certainly is a good reason to report him, yes.