No, your very right about the weights. But even if pushups are hard for him in the begining, it's something he should work on regardless; especially if he wants to box. I alone do a couple hundred pushups every training session. Most of them done during minute long round breaks inbetween rounds, I also make my students do them all the time, but that might just be me.
If your trainer won't train you because you have bad stamina then he/she is a worse trainer for not giving you a chance and help, find a different trainer that will work with you towards your goals. Seems like the trainer you mentioned is basically judging the book by its cover.
The trainer might be looking for him to have some personal motivation so the trainer is not wasting his time on someone that does not want to get into shape in the first place.
Yeah, this is the reality of many coaches in boxing gyms. If they don't see natural talent right away they barley take notice to them and don't give them much of a chance. People know how hard it is to get by in life being a professional boxer, it's just as hard being a coach, they are all looking for the next student to get them to the top as well.
