From what you’ve written, if this is his intention, I would say he chose to euthanize her. I worked in hospice for several years as an aide, and there are times when a feeding tube is not used out of compassion towards the person’s immediate comfort. For example, when a person’s body is shutting down (“active death.”), the act of digestion can actually bring them more pain and suffering. There are other factors, however. I’m not sure how invasive it is to replace the feeding tube. Some go down the throat, others are inserted through the belly. Even if the person’s vital signs are presently stable, I think it could be argued that there are cases where the risk of causing her suffering by the procedure could merit not replacing the tube. Physical pain, risk of infection, if the procedure involved in replacing the tube carried a high risk of death, etc. But if the only reason to not replace the tube is to avoid the difficult life of living as a quadriplegic, that is not sufficient reason to withhold food and water. This is my opinion, based on what I’ve read and experienced through the years.
I pray for your friend, her husband, and you. May the Mercy of God open our hearts to see and act on His Holy Will. Whatever happens, may your friend be blessed with the Graces she needs for this life and the life to come.