There is no reason to mourn a son as lost who is a religious, still less to fear for his delicacy of constitution.
1. If God makes your son His son also, what do you lose or what does he himself lose? Being rich he becomes richer; being already high born, of still nobler lineage; being illustrious, he gains greater renown; and -- what is more than all -- once a sinner he is now a saint. He must be prepared for the Kingdom that has been prepared for him from the beginning of the world; and for this end, the short time that he has to live he must spend with us; until he has scraped off the filth of the worldly life, and wiped away the earthly dust, and at last is fit for the heavenly mansion. If you love your son, of course you will rejoice, because he goes to His Father and to such a Father as He. Yea, he goes to God. But you lose him not: nay, rather through him you gain many sons. For all of us who are in or of Clairvaux, acknowledge him as a brother and you as parents.
2. But perchance you fear the effect of a severe life upon his body, which you know to be frail and delicate. But of such fear it is said, "There were they brought in great fear where no fear was" (Ps. xiv.9). Reassure yourselves, and be comforted. I will be to him a father, and he shall be to me a son, until the Father of mercies and the God of all consolation (cf. Rom. xv.5) receive him from my hands. So do not mourn; do not weep. For your Geoffrey is hastening to joy and not to grief. I will be to him father, mother, brother, and sister. I will make the crooked straight for him and the rough way smooth (cf. S. Luke iii.5). I will so order and arrange everything for him that his soul shall profit and his body not suffer loss. Moreover, he shall serve the Lord in joy and gladness, and shall sing in the ways of the Lord that great is the glory of the Lord (Ps. cxxxviii.5).