I am a new dad, and I want to know ways that I can support my nursing wife. Any advice for me?

My lo is 12 weeks old. He has started to eat/sucks his hands n fingers about 3 weeks ago. Also, saliva drools frm his mouth. Whenever i cradle him, he will start to suck my left forearm. I am a ebm mum. Is my lo teething? But its too early. I tried to stop him frm eat/suck his hands. Should i let him be n this is passing phase?