Saying "roam and get others fed" is like saying "just dodge the Nid spear" it's an answer that means nothing. You can't guarantee your roam will be successful and you also risk your carry dying and giving up free plates or turrets.
If your carry is playing poorly but not tilted or toxic do not abandon them, stay with him and protect him while looking for free damage if you're a mage support or waiting for jungler if you're an engage support. Lord help you if you're a utility support, all the gods have abandoned you.
Anyway, roam only when it's safe and communicate with pings or text that you're doing it. Don't assume mid will just catch your drift and be there for you. Roam into enemy jjungle with your jungler if he's going that way but don't ask him to, he can be making gold elsewhere while you turtle with your carry instead.
Use all your wards plus a pink once you've lost your first turret, and just let you carry soak up the free gold and xp, stay with him but keep an eye on your mid in case you need to head over. Rarely in bronze/unranked will bot switch to top after taking the turret but if they do leave your carry one time to help top. You, your jungler, and top should be enough to shut that push down. They will not return if you kill them both, most likely.
Good luck and it goes without saying you should def pick up the high damage/impact supps and leave enchanted behind. Ardent meta had them all gutted.