Thoughts on how the Terrans will cope with Human Family Member Death
(Inspired by @wiltyard's post)
I would assume the Terrans are aware of the life expectancy difference between them and their human family right now. They have witness human death twice, and transformer "death" twice. It would be weird if the parents haven't yet talked to them on the topic of death. In addition, Jawbreaker was well aware that transformer life expectancy is longer than "10 thousand years".
Thoughts on their reactions:
Nightshade takes it really well. They are probably aware of the fact even before they started regarding Alex and Dot as their parents. (I'm going down the path of S1E13's early storyboard, where Nightshade took some time to actually accept the human Maltos as family.) They would continue to take it really well throughout the next 100 years. They would be prepared for their human family's aging and take good care of them. They would do their best on researching human medical problems but at the same time respect their medical decisions. They would be present at all the funerals, probably even giving an eulogy if Twitch and Thrash are not present. They would be sad to lose them but they won't break - at least at first. They feel more like the type to break years/decades after the funerals.
Hashtag also realized this fact really early. She kinda just brushed the unpleasant thought away, unwilling to think too deep into it. When her family is talking about the topic, she would pretend she's taking it well but is actually quite terrified. She might feel more comfortable talking to non-family members about this. Eventually someone (Twitch?) will notice and approach her. But when the time actually comes she might still need a while to process the loss. I can imagine the grandkids / great grandkids of Robby and Mo asking their parents "Why does great aunt Hashtag stop visiting?" because she kinda just disappeared for years/decades after Robby and Mo passed away.
Twitch would be aware of this early too. She would feel obliged to be mature, thinking that she needs to stay emotionally strong for her family. Her stress is obvious thought - she's hyperactive, overworking herself during trainings, helping too much with the family chores, etc. Robby would talk to her about this, express his own insecurities on the faraway future, and they will figure things out. When death is actually approaching, Twitch would be quite stressed again. She would push all her important work aside to take care of her parents (even though they already have more care than they need). She would try to stay with them all the time, saying she's more suited for the job because she's about human height and doesn't get tired. And she would really, really want her human family to stay, to the point that it might be a little bit unhealthy.
Thrash is aware of the life expectancy difference, but it would take him a while to realize what this actually implies. The moment of realization would be a shock for him, then he would be in denial. Mo might actually fuel in with the denial, saying they might have a longer life expectancy due to Quintus power. He would be quite angered by the time they realize Quintus power doesn't work this way / or when one of his human family express the desire to live a normal life and die naturally. It's a quite standard 5 stages of grief except that he would be stuck in an endless loop of denial and anger and bargaining. I think he would be the one who harbors the strongest negative feelings over this, and it will be a recurring thing throughout his life. He would snap if someone outside the family brings up the topic. And he might not be present at the funerals. Losing Mo would definitely be a devasting thing for him - the bond between them is just too important and too special. He's her Rocinante and he feels incomplete without her.
Jawbreaker would be very obvious about not taking it well. He probably wouldn't realize the life expectancy problem on his own and needs to be informed, then he just starts bawling his eyes out, which is honestly a relief for Dot and Alex because this is the same reaction Robby and Mo had when they were first introduced to the concept of death (at the age of 5 or something). This is a recurring thing for him too - for a few years, whenever someone brings up this problem he just starts crying. I think he would say some innocent disturbing things like "I would die with you! 🥹" He would probably accept a religious/spiritual explanation like "We will still be with you even though you won't be able to see us or interact with us. / We will meet again in afterlife." He might become religious solely for this reason. But which religion? Can he still "join the Matrix" or "join the AllSpark" if he was born from the Emberstone? But then can humans join the AllSpark/Emberstone? Should he pick a human religion instead? Can a terran join human heaven in afterlife? How does reincarnation work? Can he reincarnate into a human? Could he be the reincarnation of a human? His family would need to deal with questions like these for a good while (which is actually really helpful for all of them).