There's no rule saying you can't mix vegetables and ornamentals in the same garden. Furthermore, some gardeners line out ornamentals in the vegetable garden while they bulk up or until space becomes available elsewhere. Providing each has sufficient space and ornamentals do not interfere with cultivation and harvesting there is no problem.

Does it have areoles? Can't tell from the picture. If no areoles are present I'm thinking it may be a stem succulent of some type. Some Huernias like schneideriana grow extremely long. Have you seen it bloom?

Yup, agreed on the ID. You could probably take cuttings a few nodes long & pot them back into mother plant's pot, to make it look even more full & lush.

i would propagate some smaller pieces ... being very aggressive in cleaning them [a much easier job] .. and when those have rooted.. i would get rid of the old monster ... and to be clear ... when they say rinse it with water ... they mean a spray just short of ripping up the tissue ... not just a low pressure rinse .... i suspect they will root easily: https://duckduckgo.com/?q=Cordyline+fruticosa&t=ffcm&ia=videos&iax=videos might be interesting to compare how similar the propagation is ... getting a new plant rooted... is changing your very old plant.. into a vibrant new babe ... plus the new media.. etc ... by the time you are done.. you will probably have duplicates to spread all over the family ... or friends .... and.. while i was rooting some cuttings.. i would leave the old plant alone .. until i succeeded with rooting new ones ... btw: besides the webbing.. have you seen any other damage consistent with mites??? .. its called stippling .... https://duckduckgo.com/?q=spider+mite+damage&t=ffcm&iax=images&ia=images ken https://hgic.clemson.edu/factsheet/integrated-pest-management-i-p-m-for-spider-mites/