How to deal with a disabled tenant

[Baha Acuner]

Hello BPers, 

I have a tenant who has been month to month for 2 years now. About a year ago she got involved in a car accident and her leg had to be amputated. Before you think I am a heartless money hungry landlord, please note that they are living in a property with a rent much lower than market rate because they have been my tenant for more than 4 years. I haven't raised their rent during this time. 

Their rent payments have been very erratic , late 7 times in last 12 months for instance. That's why I talked to her last February and got her commit verbally to leave the property at the end of July. When I texted her last month to check on her, she mentioned her disabled status and she said that she needed to stay in the property because they still haven't located a prosthetic leg for her yet. 

I didn't reply to her to not get myself in a bad situation with law but at this point I need to have them out of the property. Should I send them a 30 days notice? Would I be violating some laws? 

Thanks