Yes, that is a PICC line (peripherally inserted central catheter) and the two tubes are called lumens (basically meaning 'tubes' to us uninitiated.) Central catheters are usually inserted in the upper arm and long enough to reach a major vein to the heart. Due to their size they can have more than one 'lumen' which have different lengths inside the catheter to prevent mixing of different meds. They can remain inserted into a vein for longer periods barring any complications.
Obviously mounting a PICC or a central catheter on the wrist would not be practical. Also, the catheter tube is fed towards the heart - often fluoroscope guided - which appears impossible in the picture of Biden.
***Some sort of electronics gizmo makes the most sense I guess***
That is all my expert source could think of, although electronics is not his field. Perhaps something new, maybe not on the market yet. Concerning a Rosary, it is not a rigid structure as far as I know and therefore would not likely protrude above a raised sleeve. Seemingly a poor lie that only raises more suspicions.
The bottom line is that Joe Biden, 78 years old, is not a viable candidate for Presidency of the United States - laughable, really. It is emblematic of the Dem's message that they hold the electoral process in contempt - just like all authoritarian governments.