What does marijuana actually do to your body, as in long and short term side effects, that I can explain to my 18 year old nephew who will not quit?

Marijuana. In the short-term, mj can cause feeling of euphoria and increased appetite, which are not necessarily bad things. But it can impair your ability to perform tasks requiring concentration like driving a car, make you sleepy with red eyes,  reduced social inhibition and reduced short-term memory or anxiety. Long-term side effects include infertility due to reduced libido and low testosterone.
Mary Jane. 400 characters to explain, not possible concern is why does someone want to escape? They r escaping from? I am not judgmental or proposing that there is always a solution. If we aren't all trying to escape something we are lying. The general outline of what you're looking for /available on the internet. I propose that what you generally find on the internet is not really what you want?