Assalaamu alaykum. After my husband's promotion, we thought to send my in-laws for Hajj but are not able to do so financially. Also, my father-in-law is not ready to go yet because of some medical reason, and my mother-in-law insists on performing 'Umrah only. What should we do? Please help us.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ʻalayhi wa sallam, is His slave and Messenger. 

The basic principle is that the rich son is not obliged to bear the expenses of the Hajj or ʻUmrah for his poor parents unless they ask him and he is financially able to do so. In this case, he should obey them out of dutifulness and kindness towards them. He is obliged to obey them in this sense, and he is not originally obliged to do so.

Ibn ʻUtahymeen was asked, “Does the father have to pay for his son's obligatory Hajj if the son is poor, and does the son have to pay for his father's obligatory Hajj if the father is poor?” He answered, “This is not obligatory because acts of worship are conditional upon a person's ability to carry them out. So neither does the father have to pay for his son's obligatory Hajj, nor does the son have to pay for his father's obligatory Hajj. However, if the father asks his son to finance his Hajj (and the son can afford it) and the son meets this request, then that is considered dutifulness towards one's parents. Therefore, it is obligatory in this sense...”

Hence, your husband is obliged to pay for his mother's ʻUmrah out of dutifulness towards her as long as she has asked him to do so and insists on it. If her husband is sick and cannot travel with her and you cannot find any of her mahram (permanently unmarriageable) men who can accompany her and she had not performed ʻUmrah before, then she may travel with trusted company, as underlined in fatwa 82195. It is better for her to travel in the Hajj season so as to perform both the obligatory Hajj and ʻUmrah.

As for your husband's father, you are not obliged to do anything for him in this regard as long as he is not ready to go, cannot go, or does not want to go. If he is physically unable to go because he cannot endure the journey, then you can appoint someone else to perform ʻUmrah on his behalf, preferably his son.

Allaah knows best.