I make goat rugs.... they are modelled on mini horse rugs and are guaranteed to stay inplace and not slip.
As far as feed goes change to cattle nuts, loss of condition can be due to lack of a number of important minerals including COPPER. Don't forget goats need as much copper as a cow to maintain their body condition, and all goat feed is made safe by including SHEEP minerals mainly.
Allen & Page do a feed called Fast Fibre, which you soak for a few minutes before feeding... I have used this very successfully on old goats.... my oldest was 19 !! She probably has a problem with the harder Alfa A... try Mollichaff Condition instead, it is much softer. I have just changed my 30 year old horse onto it and he is eating much better now.