Should we accept a young man's proposal for my sister when he currently lacks the necessary funds for marriage, especially with my sister continuing to meet and contact him despite our request for him to wait?

The guardian of a girl should fear Allah concerning her and facilitate her marriage to someone who proposes to her if he is a man of religion and good character. This is based on the saying of the Prophet, peace and blessings be upon him: "If someone whose religion and character you are pleased with comes to you [to propose], then marry [your daughter] to him. If you do not do so, there will be tribulation on earth and widespread corruption." Facilitation in marriage is obligatory, based on the words of Allah the Almighty: "If they are poor, Allah will enrich them out of His bounty" (An-Nur: 32), and the words of the Prophet, peace and blessings be upon him: "The most blessed marriage is that which has the least burden," and "Marry, even if it is with an iron ring." It should also be known that the suitor is a non-mahram (definition) to the fiancée, so he should not be alone with her, nor should she meet him or contact him by phone except according to Islamic regulations.