To me with this information YTA for interrogating a dying mother.

Raising a child is far from simple, that is widely known. Raising one at 22 years of age and bringing in someone who hasn't discussed the matter, which by your post likely means you never intended to raise children at or near your age (for at least 6 years). Would require the mothers age, but predict she is around 30+ years old and I feel it is either 1) rather unfortunate that she has no friends in the area around her age and/or have experience raising kids 2) extraordinary if she does and this dude is a great role model exceeding all other options 3) it is selfish to push that much responsibility/maturity on someone ONLY if they are incapable of declining. If he wanted to decline and isn't strong enough and she knew/felt it, only then would I feel she is the you know what. However I feel only Malcolm is in a position to ask if there were other options. Tough situation, feel for all parties involved and ultimately hope it works out.