Also I have had a 34 year old man living with his mother because of a handicap.

There is a direct loan program for very low income and housing for the elderly and handicapped. 

Of course, we were monitoring the situations and asked neighbors to quiet down on occasions, but because they still occasionally made noise (regular household noise, not massive, all-night parties), and I didn't evict, then I'm not accommodating her needs.Does anyone know of any special accommodations that need to be made for mental health reasons (as opposed to handicapped access, etc) that I need to know about before going to court?

@Mathew Schroeder  Sawatdii kaa & Kap khun kaa- yes, I agree and would love to invest closer to my US Broomfield, CO, home base, however, living in The Kingdom here I feel rather handicapped at my ability to locate deals.   

A good example would be if a handicapped tenant were to want a ramp installed at one of my properties, I'm legally obligated to allow them to do this.

It's actually two handicapped persons, both in wheelchairs, very sweet ladies.

Wouldn't having an existing mortgage handicap you on the next one?

He also has a restraining order on him for assaulting the handicapped tenant on the second floor.

@Kyle Jeane this will depend on the area and topography but generally if your doing slab on grade the most important design features are main level living, open floor plans, easy access, minimum 34” interior doors for wheel chair access, handicap accessible bathrooms with grab bars and easy access showers and or walk in tub.

Most of the answers you get here are going to be specific to the US and have that bias, so you will have a pretty severe handicap with this question because real estate is local.