Bi-polar Mother in Law and my marriage

My recently-diagnosed mother in law cam over a few weeks ago (while my hubby was away on business) and launched an attack on my parenting skills. She accused me of abusing my daughter and causing suicidal thoughts in my son and threatened that the kids would be taken away from me. None of this is true - not even a little bit. I tried and tried to get her to stop in a pleasant way, but she just kept hurling the abuse, so I demanded that she leave the house. She wouldn't leave, so the only way I could get her to go was to agree to be a better parent.

It wasn't until a few days later that I put two and two together and realized that she had been in the hospital a couple of days prior because her meds were making her sick and that she was probably under or un-medicated at the time of her visit.

My question is, were her actions a direct result of a manic episode, and therefore I should be extra forgiving? Or were they the calm, collected and well-thought out ideas of a medicated person who has spent a good, long time trying to drive a wedge between my hubby and I?

If these accusations were as a result of her disease, is it safe to assume she is well enough to spend unsupervised time with my children? There has not been a further outburst, but she continues to insinuate that she is a better parent than I am.

It should be noted that she was an abysmal mother - abandoning her kids over and over again, went through 3 marriages and divorces, and 6 different co-habitating relationships while my hubby and his brother were under 15.