I would definitely try to work out a solution with her first before you start trying to "take" him. Even if the lease was verbal, it was still a LEASE, not a sale. Hopefully she will just let you have him, either free or for super cheap, since she was in such a fix when you took him over, but if she decided to be nasty about it, she does still technically own him and could show up today and take him back since you don't have a written contract. I would be super careful approaching this if I were you. It would be different if it were an abandonment case, but she only agreed to a lease, and could claim that she was letting you lease him in good faith without checking up on you every other day, so she still in in legal standing.
"Keep a leg on each side and your mind in the middle"