Could This Really Bust Up a Potential Relationship?

My friend has a strange sitch on her hands. She and her ex spend about 24 hours a week together with their granddaughter, They raised her for a period of time, and feel that it is necessary to continue on with her in that same fashion. They are not ual with each other, there is no relationship, they do get along, however. It gets sticky,,,,,she has a very good friend with whom she would like to know even better :). He seems to have a problem with the whole granddaughter situation and thinks they are prone to ual involvement though that is not the case at all. What can be done here? She will never budge because of the baby, who is nearly three. They as a team were and are still very necessary to her as she doesnt have a very stable home life, and they provide her with the stability she needs at this tender time in her life. I think the good friend needs to understand and get more secure with himself and applaud her, am I right or not???