Does a son touching his ill father's penis for the purpose of cleaning it after defecation invalidate the fast?

Touching a man's private parts or your own does not affect the validity of the fast nor invalidate it. However, it does nullify ablution (wudu') according to the preponderant opinion, based on the general saying of the Prophet, peace and blessings be upon him: "Whoever touches his private part, let him perform ablution." It is advisable to avoid direct contact with the private parts by using a barrier, such as a glove.