3.5 yo has multiple, severely intense meltdowns per day

In the past month, it has intensified. I think probably related to jealousy over 6 month baby sister.

I'm very close to seeking professional help.

My question in the meantime is, I know you're supposed to stay calm and ignore the tantrums. But if we ignore, he will find something to destroy. If we intervene, we get assaulted. It's a lose-lose situation.

I'm at my wits end. Do we really just ignore him and let him trash something (as long as it's not dangerous)?

As soon as we intervene, it seems to prolong the meltdown. Any interaction seems to prolong it. He will bang on door, kick, scream and whine.

He also won't let anything go. He will continue to argue the point afterwards, so we can't even talk about it when it is finally calm... for fear it will start him off again.

Our quality of life has taken a nose dive. This evening it was non stop for 3 hours, it's now 8pm and he's just started again over something else. I just want to cry.