from your post, it sounds like your mom has died ?
there is nothing you do to "close a trust". assuming you still have the paperwork, assets can always be added to the trust. and even if you dont have the trust document, you could probably get away with it, if all the beneficiaries are in agreement. since i am sure that all would like to get whatever is coming to them.
how are the stocks currently titled ?
if they were titled to the trust, then you have no problems. if they were titled in your mom's name, then they are part of her estate, and subject to estate laws. if there is a pourover will, then the assets could "pour over" into the trust, where you could then distribute them, because you are the trustee.
however, they would be a "willable" item. the brokerage company is not gonna give you the funds, until they can be indemnified that no one will come back and sue them. my understanding is that this is what the "probate papers" do for you. the court appoints you legally as the executor, and then the brokerage company can feel free to give you the funds, because you have the papers that make you the legal owner.
once you are the legal owner of the funds as executor of the pourover will, then you can simply place them in trust, and distribute them accordingly.
if you dont have the trust, and you get the funds, you can still distribute them from your own account. however, i would get some sort of signature from everyone that they received their share of the funds in a satisfactory manner.
