What is the brownish-white fluid that is discharged during the day without lust or odor: Is it wadi or mani, does it necessitate ghusl, what is its cause, and does it require consulting a doctor?

The white discharge that often appears after urination is "al-wady" (a prostatic fluid). It does not necessitate ghusl (full ritual bath), but rather requires istinja (washing the private parts with water) or istijmar (cleaning with stones or other pure materials). It is among the things that nullify wudu (ablution) if its discharge is habitual. However, if it is present most of the time, it is treated like سلس (incontinence), in which case one performs wudu for each prayer when its time enters and prays both obligatory and supererogatory prayers with that wudu. There is another opinion that does not consider it nullifying wudu if it is present most of the time (like the Maliki madhhab). As for the health aspect, one should consult a doctor.