So my parents are retired and my mom has Parkinson’s and a bad hip so starting to require more day to day help. To ease the burden on my dad they are going to move next to mine and my brother’s family so we can all help out. I own 4 acres so we are doing a small pool house/ MIL suite. Just a one bedroom with a single car garage for them to live in. Here is where I am not sure we did the smartest thing. Instead of selling them a small section of land and having to replot like we did for my brothers family they offered to pay for the build and it will be on our land as if we just built a pool house but they are funding it. To pay for it they are selling their current house that they have been in for 30 years and was paid off. For the build they took out a heloc loan to cover the costs and then will pay it off once they move and sell the house. Looking at getting somewhere around 340k for their house and spending right at 200k on the new build. My question is what are the tax implications going to be from the sell of their current house. Also since they are paying for build of the “pool house” on my land is that considered a gift that needs to be disclosed. We live in Texas. If I have left out any needed info please let me know. Thanks in advance for any and all advice.