Is slaughtering a prerequisite for distributing meat to the poor, the needy, and relatives, or does buying meat and distributing it to the poor suffice, and is there a reward for every drop of blood?

If your father slaughters a cow every Ramadan as an offering to Allah, this is a righteous deed. However, giving charity to the needy in Ramadan earns greater reward, and it does not have to be a slaughtered animal. Adhering to slaughtering in this case and believing it to be an act of worship specifically in Ramadan is an innovation (bid'ah). Charity in Ramadan is charity given at an auspicious time, and it is best given to those who need it most, in the form that benefits them most. People often prefer money over food. What some people do during Ramadan nights, such as excessive slaughtering and banquets attended only by the wealthy, is not legislated and was not practiced by the pious predecessors. It may be akin to performing a ritual in the wrong context. It is more appropriate to refrain from slaughtering and instead buy meat and distribute it to the poor, in order to avoid incorrect beliefs, while noting that giving charity to the wealthy is permissible.