Dropped Pastern

We currently have one healthy 21 year old guard llama on our alpaca farm. We'd like to add a llama or two to the herd to give her some guard back-up, and also because we are enamored by llamas (who isn't??).

We went to visit a lovely local llama farm recently and are interested in a 4 year old guard llama that the owner is willing to sell to us. However, she said that she will only sell her if we also take her 12 year old llama mama. The owner tells us that they have never been separated and she wants to keep them together. Both llamas are guards and have wonderful dispositions.

The problem is that the 12 year old mama llama has totally dropped pasterns. The reputable owner, who I know isn't trying to take advantage of us, tells us that the pasterns have been dropped for a few years and the llama manages quite well and seems unaffected by them. She is not overweight, in general good health, and is walked around the neighborhood regularly with no issue.

So the questions are: Is this a wise decision to buy this young llama, knowing that we will also be taking on her mother with dropped pasterns? Is this only going to lead to heartache? In your experience, if the mama llama is kept at a good weight (and I read on a forum that selenium might help?) and not bred, might she remain healthy for several years, or is this just asking for trouble? We are new to this and want to avoid obvious issues, if possible. We are willing to take a small-ish calculated risk, but if the outlook is dismal, we'd like to know ahead of time.

The second question is: is this a genetic trait and should we be concerned about the 4 year old 'baby' developing this condition, or passing it on to her baby?

Thank you!
Kris