Is it permissible to divorce one's wife while not possessing the financial means for divorce, or is it obligatory to be patient until these means become available?

If the wife leaves the marital home merely to request a residence near her family, she is sinful. You are obligated to provide her with a suitable dwelling where she feels safe. If providing the home the wife requests does not involve undue burden or difficulty, then do so. The intervention of the wife's family should be for reconciliation, not for causing discord and incitement. Indeed, the Islamic law has made them a reference point, as Allah Almighty says: "And if you fear dissension between the two, send an arbitrator from his people and an arbitrator from her people. If they both desire reconciliation, Allah will cause reconciliation between them." (Quran 4:35) Do not rush into divorce; involve sensible people and those of virtue for reconciliation and seek help from Allah, as Allah Almighty says: "And if a woman fears from her husband desertion or evasion, there is no sin upon them if they make terms of settlement between them - and settlement is best." (Quran 4:128) If reconciliation is not achieved and she desires a divorce, you may stipulate that she forfeits her rights, as Allah Almighty says: "But if you fear that they will not keep within the limits of Allah, then there is no blame upon them for what she gives to free herself." (Quran 2:229) If she does not desire a divorce, you may keep her in your marriage and continue to attempt reconciliation, or you may divorce her, and what is due to her from you becomes a debt on your conscience, as Allah Almighty says: "And if there is one in [financial] difficulty, then [let there be] postponement until [a time of] ease. But if you give [from your right as] charity, it is better for you, if you only knew." (Quran 2:280)