For the rooster in the photo, yes, crossing him with a Delaware hen will probably produce sexlink chicks.
But I'm pretty sure he is not an ISA Brown rooster. With that much red, he is more likely to be a Production Red, or a poor-quality example of some other breed (Speckled Sussex? Rhode Island Red? The white dots are a bit wrong either way.) Or, depending on where you got him, he might be some kind of backyard mix. If both of his parents were ISA Browns, that does not make him an ISA Brown, because ISA Browns only come from a particular cross, not from breeding them to each other. The way the sexlinking works, you cannot use the sexlinks themselves to make more of that kind of sexlink.