"I’m not ready. I don’t have any training." (Grace for Rocky!)
It's been a long long long journey.
The four years spent traveling from Tau Ceti to their homeworld had been brutal. Maybe not for them but for Grace, starvation had been an ominous shadow looming over him. It'd been horrible watching his body fail, slowly, bit-by-bit, because the Taumoeba just wasn't sufficient as a long-term food source. Too little nutrients that a human needs. And as much as Rocky would've been willing to share with him, Eridian food would only poison him.
They'd been afraid of the day when his lungs wouldn't fill with breath anymore, when his heart would stop beating in his chest, when they'd be left alone alone alone all over again.
But they've made it. They've made it home and brought back hope.
It'd been a bit messy at first, trying to establish communication between the Hail Mary and ground control and then explaining the situation. The answer to the astrophage eating their sun, Grace, his deteriorating condition. How he was just as responsible for saving both Earth and Erid as Rocky was.
Naturally there was some hesitation at first. But, eventually, arrangements were made. The best scientists planet-side would find an answer, both for his caloric needs and to make him a suitable, permanent living space. But that requires crossing a hurdle;
At least for the rest of Erid, it would be. They'll have to make sure the scientists don't get too excited about Grace and his ship. No doubt, even with the circumstances, they'd be amazed amazed amazed.
"No training required for this," Rocky chirps, the translator giving his human-voice something of a confident tone. "Scientists come onboard, exchange information, help fix food problem, save Grace. Simple!"
They've gone over this with him already. It's an attempt at reassurance. But, after a quiet moment, they trill softly,
"...Rocky doesn't feel ready, either. To come home."
Even after docking, they haven't left Grace's side, let alone actually disembark from the ship. They know Adrian is waiting for them, ever-loving and patient. But what about the families of those who died on the Blip-A? They would want answers for what happened to their loved ones. Answers as to why only Rocky came home, and with an alien no less.
And they've spent so long alone, both with and without Grace, that the idea of seeing their own kind again is, admittedly, scary. But they both can't stay on the Hail Mary forever, and the scientists will have to come onboard eventually if they want to save Grace from starvation.
At least they'll have proper xenonite suits so that they won't have to roll around the place in glorified hamster balls (whatever those are anyway). They were courteous enough to make one for Rocky, leaving it in the docking airlock for them.
"Grace is bravest human Rocky knows. Brave brave brave. Will soon be bravest human Erid knows!"