I am pregnant and my mom and brother came over to help paint the baby room. After the first coat a couple days later I noticed the tub drain was very sluggish. I forgot to tell them and today my brother cleaned up from the second coat using the same drain and I see chunks in the tub! What can I do to unclog it? We have an upstairs bathroom so I can't check the trap from the crawl space.

I see chunks in the tub! What can I do to unclog it You can snake your tub from the overflow, (see image) and try to break it up and send it out to the main.
To snake your tub remove the two screws holding the chrome face plate and pull up and out on the linkage and plug. Feed your snake in through the opening. You will run into the return bend of the trap about 18 inches down but crank and work your way past that you should only have 6 or 8 more feet to run out. Flush with a tub of hot water. Good luck and thank you for rating my answer, Tom

In addition to Tom's advice: Latex paint dissolves in water. It probably mixed up with already present hair in the trap. Try to fill up the tub with HOT water all the way to the rim and drain it. Do it several times. It may help to push the clog down the drain