What is the ruling on zakat for the aforementioned current wealth, and what is the ruling on what was given to the siblings, and do they still have rights, and how does one pay zakat from now on in light of existing debts, investments, and the change in the nature of work to services?

Zakat is not obligatory unless the wealth reaches the nisab (minimum threshold) and a hawl (full lunar year) passes over it. An exception to this is produce, for which zakat becomes obligatory upon harvest if it reaches five awsuq (a specific measure). There is no zakat on personal possessions such as a house or a car. Zakat is obligatory on commercial goods that were purchased with the intention of trade and offered for sale. In this case, their market value is assessed, expected debts are added, and due debts are subtracted. If the remaining amount reaches the nisab, zakat becomes obligatory. This process is carried out annually, and the muzakki (person paying zakat) must strive and investigate to clear their liability.

There is no zakat on fixed assets not intended for sale, such as service equipment and leased buildings. What was previously given to the poor and needy from zakat does not count unless it was intended as zakat at the time of giving it, based on the Prophet, peace and blessings be upon him, who said: "Actions are but by intentions." So, if you recall what you gave with the intention of zakat, then complete the remaining amount if there is still zakat due from you. The money you gave to your brothers is lawful for them, and the zakat on this money is obligatory upon them according to the previous details.

In summary, zakat is not obligatory if a hawl has not passed over the nisab of wealth or commercial goods. However, if a hawl has passed and you possess the nisab of cash or goods prepared for trade, zakat becomes obligatory upon you, and what is given to the poor and needy without the intention of zakat does not suffice for it.