How dangerous is it to have blood clots around organs?

My mother recently had pain in her abdomen and finally went to the doctor, he immediately sent her to the ER and she has to spend the night there maybe more. seeing my mom cry and be scared makes me scared. idk what it is called so if you know that would help... She apparently has multiple blood clots around her liver, and if one detaches it can go to her heart or brain? im very worried. i cant look up anything about it. her doctor has only heard of it,never seen it. any help at all?