Is the decision to marry at this time considered wrong, given the difficult financial circumstances, the mother's illness, and her debts, and what should be done a month before the marriage?

Your desire to marry and hasten it is not considered an act of disobedience (ʿuqūq), especially if you fear falling into what is forbidden (ḥarām), for it then becomes obligatory. It is also a cause for attracting provision (rizq), as it is stated in the Hadith: "Three groups of people, it is a right upon Allah to help them," and among them he mentioned: "the one who marries seeking chastity." However, if there is no pressing need or temptation, and you are able to delay marriage to improve your situation and that of your family, there is no harm in it. Your consideration for your mother's feelings is a form of filial piety (birr). Increase your supplications (duʿāʾ), and ask your mother to supplicate for you for the facilitation of your affairs, for the supplication of parents is answered. To relieve worries and pay off debts, say: "O Allah, I seek refuge in You from worry and grief, and I seek refuge in You from inability and laziness, and I seek refuge in You from cowardice and miserliness, and I seek refuge in You from the burden of debt and the domination of men," and "O Allah, make what is lawful sufficient for me against what is unlawful, and enrich me by Your grace, independent of anyone other than You."