I wish I had more details on your situation but off the top of my head, I would say it is better to stay where you are.
See if your mom would lend you the money to pay the landlord and get up to date or even up to date and a bit ahead if she can afford it and work out a slow payment plan with her.
Once you move back home you will get into the habit of not paying rent and unless you are a good saver, you will find other things to spend the money on. Besides that, if you are a writer, moving in with your mom could really hamper your creativity to make your income even worse. You and your mom may not see eye to eye on how your days should be spent. You may have a great inspiration and want to stay up all night writing and she may want you to walk the dog and do chores starting at 6am. I don't know the situation but I think you see what I mean.
Since you like where you live and have a cool landlord, stay put. Your mom isn't going anywhere so that can always be an option but one I would use as a last resort.

By the way, what type of writing do you do?