Sister in law now wants family to be executors of her will. Advice?

Please don't take this as a rant or diss on my S-I-L. Please see it as my wanting to give input to my husband & 2 adult children who are considering being an executor/trix of my sister-in-law's will. I realize it is their decision, not mine to make. She can be as nice as pie one day and be sullen and hateful the next. She is very much for herself. She is a source of discord to my husband and to one of our children. She had "disowned' them & was going to will her residence to a charitable organization. Now that she is up in years & only has my spouse & our children, I am suspicious of this sudden attitude change. She is shrewd about money. She has had contact with elder care lawyers. Our state, PA, has a filial responsibility law. Would my husband or our kids be financially responsible for her care (if care such as nursing home care needed in the future) if they sign on this will? She is dangling the carrot of leaving her residence to them. They do not like her, but the thought of the residence may be an enticement. Cannot a lawyer be made an executor of a will? Please advise. Thank you.