Tax Filing Requirement for Trustee involving death

Many years ago, my wife's brother (Curt) had been married, then divorced and later came down with Multiple Sclerosis.  In that marriage he had 2 daughters, that are now grown up and married. Before he died, my wife's father set up a special Trust for Curt that held about $30,000 and was to be used for his special needs. Because of his medical condition and financial situation, the trust was only to be used for things and expenses that would better Curt's life.  My wife and her sister were co-trustees of this special trust. Through out the years, the $30,000 was used slowly used up and last year, the last remaining $5,000 was given to Curt for expenses before he passed away. The trust account was held by Morgan Stanley and was fully depleted.

Last May, (2022), Curt passed away and his daughters took care of his funeral expenses and other assets. My question, is the following:  As trustees and co-trustees of this special trust, does my wife and her sister have any obligation or requirement to file any type of tax form regarding the trust.  My wife and her sister, never received any money from the trust and only acted as a fiduciary in approving funds from Morgan Stanley to Curt. If a tax form is required, which form and would it be the trustee or Curts daughters that are required to file it.