Does excessive thinking and obsessive fears about the death of one's parents, despite knowing that these thoughts are wrong, necessitate treatment?

It is obligatory for you to be kind to your parents and to accompany them with goodness, in obedience to the words of Allah the Almighty: "And your Lord has decreed that you worship none but Him, and that you be kind to parents," and His saying: "and accompany them in [this] world with goodness." As for the duration of each of their lives, none knows it but Allah, and the pen has dried concerning what will be in it, as Allah the Almighty says: "And Allah will never grant respite to a soul when its appointed time has come," and "And for every nation is a [specified] term. So when their term has come, they will not remain behind an hour, nor will they precede [it]." And since you know the error of indulging in this kind of thinking, you should have a sincere resolve to turn away from it and occupy yourself with what is more important for your religion and your worldly life.