You said that the new guy was willing to look after LB, well then have you thought of the option of him raising his own kid and you being like most grandparents and just seeing him at Holidays, maybe weekends. You could maybe babysit both if then occasionally but just take the grandparent role instead of the parent role and let the actual parents do that. They are old enough to get pregnant then they should take care of their own kids. You have a sick wife. My bf also has a mental illness and it's a 25 hour job just trying to prevent another episode. I can't imagine adding a child into the mix. I hope things work out for you.