The House Dems broke quorum, which means nothing can be passed right now. So if that’s true, why are Senate committees still hearing bills? The short answer is because they can. For one thing, the Senate still has quorum, so they’re free to continue referring bills to committees, hosting committee hearings, and voting on bills.
The other reason is political. In this standoff there are essentially two teams: one wants to pass bills that keep people from voting, stop trans youth from playing sports, keep people from accessing abortion, and ban teachers from teaching that racism exists. The other side wants to protect the right to vote, trans rights, the right to abortion, and focus on expanding the rights of Texans. The Senate is majority is made up of the side that wants to undermine the rights of marginalized people in Texas. Their strategy is to keep holding hearings while shutting down the voices of people whose rights are under attack.
So when we say nothing can ultimately pass as long as the House doesn’t have a quorum, that’s true. But because the Senate has its own set of circumstances, they can continue hearing bills and taking votes even though those bills will die due to the House being unable to take votes.