engagement party....

my cousin and her boyfriend are engaged and getting married in 2019 or 2020 (hasn't set a date yet) she's having her engagement party late november.... unfortunately I can not go to the engagement party because my due date is the day after. what kind of gift should I send them? i don't wanna give them money because we are not going to the shower and since I'm gunna be outta work for 12 weeks were gunna be tight on money.... what gift should I get them??? they don't live together so I'm at a loss...