Hehehe- RATS can be viscous, and 'Oh so loving.' A full grown rat would be a challenge for many a ball python-- Yes a large Ball Python around 4ft shouldn't have an issue eating an adult rat; but with Ball Pythons, (unless it is an older female) it is usually not the case. Now a red-tailed boa would make any rat a "Happy meal".
BTW, the ability of prey to fight back is why many reptile keepers feed their animals dead prey. I don't, but many do! Rats can put up a fight!
Your son, your grand-snake child, and your future rat child, should be one happy family for a while.... Wonderful rat, but his/her tail looks like a mouse tail, and not a rat tail. RATS are large and their tails are quite a bit larger too. Rats tend to have a longer more triangular face as well.
I like the colors and the painting over-all, but it gives me the impression of a mouse, and not a rat. BTW, there are dumbo mice and fancy mice, as well as dumbo rats, and fancy rats...
Never-the-less, your son's girlfriend will cherish that painting!