Sforno on Genesis 48:2/ספורנו על בראשית מ״ח:ב׳

1וישב על המטה. He did this in order to pay his respects to the presence of “Royalty” in his house to the extent that he was able to under, the circumstances, considering that he was bedridden. We observe the opposite mode of behaviour described when Mordechai did not make the slightest move indicating deference for Haman in Esther 5,9 “he neither rose nor even moved from where he was seated.”