As everyone else has already said, you really should teach your DS Polish.
I can only repeat what others have already said, my DH comes from another country and he spoke entirely to our daughter in his language. She took a bit longer to start speaking but she is fluent in both languages.
If your DH claims that he can't learn another language then just show him this video from a Polish company. It even got a whole article in The Guardian about it:-
It’s not just a Christmas ad – it’s a Polish grandpa’s heartbreaking gift to Britain
The three-minute-long film, entitled Angielski, was made for Allegro, an online auction website in Poland, and tells the story of an elderly Polish man named Robert who is beginning to learn English. The camera accompanies him taking his first steps, trying to painfully learn the basics – “I am; you are; he/she is” – and peppering his house with Post-it notes to expand vocabulary beyond the rather unparliamentary phrases he learned from a TV action movie.
The unexpected plot twist comes when we finally learn the reason behind his determination to learn English. Spoiler alert: in the final scene, he flies off to Britain to spend Christmas with his son’s family, where in a truly tear-inducing moment he meets his granddaughter for the first time, telling her: “Hi. I am your grandpa.” By this point, we – the viewers – are all in tears, sobbing quietly, and cursing the scriptwriter for taking us on this unexpected emotional rollercoaster ride.