I understand.
As for your question, is this normal? Once you start reading around the forums you will see that it is quite common, especially when someone is trying to recover OR if they say they are.
Two different scenarios. If they are going to try sobriety and recovery, that's a BIG task. It can take years. Getting sober is just the first step, then recovery, where they need to unravel the addiction and all that put them there in the first place. This can be a big trial and is tough on them and everyone surrounding them, generally.
Second scenario is that he just wants to use and wants to be able to do that freely without any pressure from anyone (you) to stop. It's difficult to know which one it is, unless he actually tells you truthfully and based on his actions so far, can you trust him to give you the truth?