I checked into a lot of this when this happened to me years ago.
In Houston there is no rent increase cap. They can raise it by whatever they want. It does not matter if you are a senior citizen or disabled.
There are no laws what-so-ever protecting the tenets, as long as the lease is up and they do not attempt to raise the rent during your lease. It's simply that rent is sky rocketing in this area.
I used to live in this gated community from 2012 to 2014. It's called McKinney Street Villas, all the patio homes are basically the same and rented for $1,500.00 - $1,700.00 a month. Now they are going for $2,000.00 +.
http://www.har.com/918-mckinney-park-ln/rent_94471877