My cofounder having 45% share is not giving time anymore, what can I do about it. (I will not promote)

So me and my cofounder(my friend)started this TalkDrill business, now for last 2-3 months he’s not giving any time to this. we both started this as part time still I am giving it my 3-4 hour every day but he’s not giving even a 1 hour a day saying he’s very busy in his job for last three months. I will say I am feeling bad that I am working on this product, I am giving more effort even though none of us is getting paid out of it right now we’re not taking any money, we’re just re-investing everything we’re not taking any salary. But if I stop working like him, the startup will die. What should I do?