Rabbi Baruch Newman explained that בא בימים means that אברהם came into each day with two concepts on his mind: the day he was born to remember his mission on earth and the day he will die and have to be judged. The בית אברהם explains that it means that he came into each day focused on the present, not on the past. The רל״ג says it means that ב is two representing שרה and יצחק and the א is one representing ה׳.
Rav Chaim Shmulewitz explains that שרה died when she heard about יצחק and אברהם didn’t die because if ה׳ is testing you then ה׳ gives you the ability to pass it, and since this test was not for her she was not able to pass it. Another פשט is that ה׳ played it up to אברהם in steps, and he also had a few days to psyche himself up. but שרה only saw the picture of him on the מזבח, so she couldn’t take the sudden news.
Rav Yanky Rubin explains that אברהם is saying that he is a גר תושב means that he is a גר in that he is willing to pay for the burial, but even if they don’t want money then they still need to do the burial because he is a תושב, a resident with the right to burial. Similarly, the אמרי חיים says that how could אפרון tell אברהם that they are two close friends? He explains that it meant that אפרון loved money and אבהרם loved מצוות, so of course אברהם would pay to bury יצחק.
The רל״ג explains that the תורה just says that אברהם eulogized and cried, but doesn’t say what he eulogized. Why? Because his eulogy was crying, recognizing how much he lost. Right after this it says that אברהם got up because a Jew cannot get depressed.
The דברי ירמיהו says that when אליעזר met לבן he said אלי without the ו, implying that if לבן wouldn’t let רבקה marry יצחק then אליעזר’s daughter would marry him. The אמרי אמת says that אליעזר thought that his daughter could marry יצחק because when he saw what type of house and family רבקה comes from and that even so יצחק was going to marry them, so then why not his own daughter?
Harav Binyomin Jacobs said that אליעזר knew that if the person he found would have מידות and חסד then since she would be giving herself over to someone else, then even if she follows עבודה זרה still יצחק would be able to have an influence on her and make her religious.
The Modzetcher Rebbe explains that אליעזר was looking for someone who would not just do חסד, but even be happy to give him the water.