If his pets have trouble surviving stuff out in the wild, they're probably not going to hit a string of 100 wins yet for the payout yet. You could work on getting a bell, give it a good laser or machine gun and ammo/cell and maybe could do it without necessarily training? But maybe not.
Save your ores of rubinus, diamond, and emerald - with enough alchemy and jewelcraft you can use a pot for fusion to combine 5 of each in a new type (the shiny stones mentioned above) which sells for more than the components. You can also give them the ores directly (also crystals) and they can sell those too, just for less combined than the jewels are worth. But you need a moderate skill for these - I think diamond, the last, needs 35 alch and 40 jewel? Something like that.
Giving them pickpocketing through gene engineer, they will steal gold from enemies they kill. This actually seems to amount to a lot because my pets are frequently training in town even though they aren't selling anything. I think they actually gain gold outright rather than steal it, because they get a lot despite killing things that don't carry much gold or any gold at all, having checked the enemies with pickpocket.
I don't know, I haven't really even focused on them all that much but my little girl and goose are about level 40 and are hitting for 800 or so. But, again, I am playing on overdose mode so their skillups are ludicrously fast.