I'm doing some research into increasing blood flow for a family member. What I found (if you don't mind). Might save someone with poor blood flow from amputation too:

take 500mg of L-arginine (NO precursor) twice daily.

L-Citrulline (found in watermelons) may be more effective than L-Arginine itself at increasing blood Arginine concentrations (Arginine it is THE substrate which the body uses to produce nitric oxide to widen blood vessels). So might want to take that instead. Source:

https://pubmed.ncbi.nlm.nih.gov/28179487/#:~:text=However%2C%20supplemental%20citrulline%20increased%20arginine,arginine%20supplementation%20itself%20in%20mice.

Curcumin also works to increase blood nitric oxide via complementary pathways (such as increasing the eNOS enzyme activity which converts arginine into NO).

Source: https://examine.com/supplements/curcumin/

https://www.tandfonline.com/doi/full/10.3109/14756360903555274

Finally, if that doesn't work, might want to take something to suppress Arginase activity like Chlorogenic Acid (from Green Coffee bean extract). This is the most potent one that is natural (present in coffee) and available on the market.

Source: https://www.thieme-connect.com/products/ejournals/pdf/10.1055/s-0042-118711.pdf

Nattokinase is a potent fibronylitic agent that can dissolve existing clots (aspirin only prevents new clots AFAIK).