I am not sure if their is a way to get a preceeding command using skill because most of axl functions work during idle mode (or no command is active).
but regarding changing line width, you can use axlDBCreateLine.
axlSetFindFilter(?enabled `("ALL" "clines" "lines") ?onButtons `("noALL" "clines" "lines"))
point = axlLastPick(nil)
lineDbid = car(axlGetSelSet())
(foreach item lineDbid->segments
axlDBCreateLine(item->startEnd, preferedWidth, item->layer)
note: preferedWidth is variable for width you wan to change
Hope this helps