Buffalo - Need Help with Eviction Advice

[Matthew Pfeiffer]

My fiance's grandfather owns property in Black Rock and currently has a tenant that has been in the hospital for at least a month now. He went to check in on the residence recently and discovered a complete disaster; complete filth and garbage littered throughout the house, cat urine and feces all over etc. It goes without saying that he has never been a very attentive landlord, however the big issue is all of his properties were recently signed over to his son (my father-in-law) and we're looking at potential future issues for him. 

For this particular property we're looking for some guidance on the appropriate steps to take in order to have this guy evicted. This is a short list of the information we have so far:

• - He's on government assistance
• - Month-to-month rent agreement (need to confirm) 
• - Case worker from a past incident told him that she was familiar with this particular tenant and that he will be an issue to evict, so we're looking at a potential dragged out process  

My fiance and I are fairly new to real estate and only own one property so far but have never had to deal with a situation like this. We would like to be able to help out her father & grandfather and also learn the process along the way. I've attached pictures to this post to show the magnitude. 

Any information or point in the right direction is greatly appreciated!