Taking a debt on one's credit card to pay for one's parent's hajj expenses

My husband's parents names were selected for Hajj this year. However, they have a shortfall of a lot of money. One-third of it. My father-in-law also has a credit card with money owing on it. However, he is not concerned about clearing his debt before going. Furthermore, he asked my husband if he can help him with the balance of the money, which my husband said he would take on his credit card. I am not in favour of this decision as it is a lot of money and we actually cannot afford to pay it every month but he is insistent. We have a family of our own and expenses every month, furthermore, my father-in-law has no sense of remorse that he is going to put his son into debt. Is this fair? Is this allowed?