there's 15mg L-DOPA /capsule.
smallest prescription l-dopa tablet is 100mg, i believe this is the starting dose, so tiny amount of l-dopa.
i've read posts here where people are taking tablespoons of mucana.

anyway, caution would make one try 1cap/day, if that has no side affects then 2, then 3 maybe.

you want to find a dose that works and doesn't have side affects. then you can progress to how often, l-dopa has a short half life, maybe 90 minutes.
the wise thing is to have him see a neuro. put him on sinemet and see if it helps his tremor, why screw around with your father's quality of life?