C. F. Keil and Franz Delitzsch on Proverbs 19:4

Pro 19:4 4 Wealth bringeth many friends;    But the reduced - his friend separateth himself.

The very same contrast, though otherwise expressed, we had at Pro 14:20. Regarding הון, vid., vol. i, p. 63. דל is the tottering, or he who has fallen into a tottering condition, who has no resources, possesses no means. The accentuation gives Mugrash to the word (according to which the Targ. translates), for it is not the subject of יפּרד: the reduced is separated (pass. Niph.) by his misfortunes, or must separate himself (reflex. Niph.) from his friend (מרעהוּ, as Ecc 4:4, prae socio suo); but subject of the virtual pred. מרעהוּ יפּרד: the reduced - his friend (מרעהו, as Pro 19:7) separates himself, i.e., (according to the nature of the Semitic substantival clause) he is such (of such a fate) that his friend sets himself free, whereby ממּנּוּ may be omitted as self-obvious; נפרד means one who separates himself, Pro 18:1. If we make דל the subject of the separatur, then the initiative of the separation from the friend is not expressed.