Are the partner's funds considered a debt owed by the questioner after the project's loss, and is he entitled to a share of the recovered capital if it is recycled into another business, or does this right belong solely to the questioner for bearing all the risks and troubles?

The worker's hand in a Mudarabah (profit-sharing partnership) is a hand of trust (yad amanah). Therefore, he does not bear the loss nor is he liable for it, unless he transgresses or neglects his duties. Mudarabah is a permissible contract (aqd ja'iz), and it may become binding if the Mudarib (worker) commences work or if both parties agree on a specific duration for it. If the Mudarabah is dissolved by mutual consent, the equipment is sold to determine the capital. If the equipment is valued and you purchase it, then the profit is yours. If you do not agree to the dissolution, then the partnership remains until the equipment is sold, and the profit will be shared between you according to the agreement. The capital is not a debt upon you unless there has been negligence on your part.