If one’s father visits his home, or if he moves in with the child, the child should offer the father to sit at the head of the table. If the father declines the offer, then the son may sit at the head of the table, but it is proper to first offer the seat to the father as an expression of respect. The exception to this rule is when the father’s position at the head of the table will violate proper standards of Seni’ut (modesty), such as if he will then be seated next to somebody else’s wife.
One should also show his father respect by inviting him to wash his hands first after Kiddush on Shabbat, and by serving and offering him food first. It is proper etiquette not to begin eating until one’s father has begun eating. One may, however, begin eating before his mother has begun eating, since mothers generally want the people at the table to begin eating as soon as they receive their food.
If one’s father visits for a Shabbat meal, the father should be given the honor of reciting Kiddush on behalf of everyone else. If, however, the father slurs the words or is unaware of the basic Halachot – such as the requirement to have particular intention to fulfill the obligation on behalf of the others – the son should recite Kiddush. Even in such a case, if the father will feel slighted by not reciting Kiddush, then he should be allowed to recite Kiddush, and everyone present should recite the Kiddush by himself.
According to some authorities, the host should recite the Beracha of "Hamosi" over two loaves of bread on Shabbat and Yom Tob, even if his father is visiting. Others, however, maintain that this requirement does not apply nowadays, and therefore one should invite his father to recite the Beracha over the bread when the father visits.
In all these cases, if the father expresses "Mehila," meaning, if he foregoes on his honor, then the child is exempt from that requirement.
(These Halachot are taken from Yalkut Yishak – Honoring Parents, beginning on p. 356.)
Summary: When a father visits his child’s home, the father should be invited to sit at the head of the table, to wash his hands first, and to receive his food first. He should also be invited to recite Kiddush and, according to some opinions, to recite the Beracha over the bread. Furthermore, one should not begin eating before his father. If, however, the father declines any of these offers, the son is no longer bound by that requirement.
