let me explain it then simply law misunderstood that jesse doesn`t want him anymore where in fact jesse didn`t want him to become his mother`s dog so he stopped seeing him all together which got law the idea that he was discarded
from this point law gave the tea "sedative" and let jesse enter the virtual world which for them were like years where in fact was one day it messes up with memories and you can do whatever the hell you want with the person and this is a "setting" that was made by law for jesse basically everything that jesse saw was fake
the purpose for all of this as we see in the very last pages is that he wanted jesse to choose him after all the failed attempts jesse actually did it at the one we saw yet law was afraid he wouldn`t be able to stay with him and so he let jesse back to reality
finally both got back together again
this is long but i hope it clears it up if you are confused about anything else just ask~
I honestly didn't understand SHIT but I read it til the end and now that they are together I'm happy.