dnd 5e – Can your familiar use the frozen spell bead from Arcane Abeyance to indirectly let you concentrate on a 2nd spell?

Yes, depending on how the spell targets creatures

Rubiksmoose gave an excellent break down of what an attack is here, but what’s relevant to this question can be found on p.193-194, PHB:

Whether you’re striking with a melee weapon, firing a weapon at range, or making an attack roll as part of a spell, an attack has a simple structure

If there’s ever any question whether something you’re doing counts as an attack, the rule is simple: if you’re making an attack roll, you’re making an attack.

As a familiar is not able to attack (excluding a Warlock Pact of the Chain familiar), but there is no mention to a familiar’s ability to cast a spell, then the familiar should be able to cast any spell that does not require an attack roll. In regards to the concentration of the spell in question, Arcane Abeyance states, as you’ve linked:

…A creature holding the bead can use its action to release the spell within, whereupon the bead disappears. The spell uses your spell attack bonus and save DC, and the spell treats the creature who released it as the caster for all other purposes.

The only places the spell would not use the familiars abilities are on the spell attack bonus (irrelevant for a familiar) or spell save DC. All other aspects of the spell would be the responsibility of the familiar, including concentration.