Hot tubs and pools have the most well documented ROI.

Here's a hot list of things I'd want to understand, and based on this, there are tons of different avenues he can go. - what is his short and long term goal with real estate investing? 

If your market isn't as hot right now or if you don't have significant equity in the home, then chances are you may be better off submitting a contingent offer and relying on the market. 

We both lost out to someone that was willing to give the Seller almost the price they were asking because they were doing a 1031 exchange were they had a substantial amount of cash and they liked the property location.This similar scenario has played out for me several times over the last few years because the market was so hot.

Renting allowed them to cover costs and build equity, while selling in a hot market helped them capitalize on the home’s increased value.Let me know if you’re interested in financing options for similar deals, happy to assist!

Expanding your buyers list is key, especially in a hot market like Houston.

You might want to think about pulling up the carpet and taking a look. (2) Maybe the water delivery piping under the floor, hot or cold, has developed a pinhole leak and is spraying onto the subfloor from below. 

Passive landlord is a long game enter anytime stay for decades and most will do just fine.Active engagement same thing enter anytime and your reward is how hard you work identifying the hot ticket at the time  access to capital etc etc..

Plus a small cutting board and "hot plate" to avoid tenants damaging kitchen counters by chopping items or setting hot pots directly on them.Gail

They can use water from the hot tub or fill up a bathtub to have water for flushing toilets.