@Tamica5. Before you engage an expensive attorney you should check whether sub letting was permitted in your lease and if it required landlord consent, or are there other reasons why he might try and withhold your security deposit?
Also, is there a not for profit rental association in Houston that might be able to help, or a govt department that regulates leases? I found this on Google, no idea if its current but may be a start:
https://houstontx.gov/housing/fair-housing/flyers/2021/english/FH-Hotline-Renters-Flyer-Final-V2-081...
I am a landlord here in OZ and in our state you must now lodge your tenants bond online with the government. At end of lease both parties can make a claim so if in dispute the govt tribunal steps in which is free for tenants, but landlords pay to apply. I think its fair.
I would never give a bond directly to a private landlord if I had the choice.
Good luck.